[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] Precautions cleaning up rat droppings?
Precautions cleaning up rat droppings? We had a rat or rats in our garage. An exterminator got rid of them, but there are droppings in the garage. How do I clean it up? Several years ago there was a virus found in rat droppings, and special care was needed to clean and dispose of the droppings.
You are referring to Hantavirus, it is found in rodent droppings and goes air born when you sweep them up or vacuum them up. More people get sick from Hantavirus each year than have ever gotten sick from mold. It makes you wonder why there is so much publicity about mold and none about Hantavirus.
The proper way to clean up rodent droppings is with a damp cloth or paper towel that makes all the air borne particles stick to it. Dispose of the damp cloth and droppings in the garbage can.
You don't need to spend a fortune to get rid of rats. Using a few basic techniques and inexpensive traps it is possible to solve your rat problem without breaking the bank.
The venerable wooden snap trap like the one made by Victor, is still one of the most effective ways of trapping rats. They are the least expensive of all rat traps and can even be purchased in bulk by the dozen in order to save even more money. One of the most effective strategies for trapping rats is to place as many traps as possible in a given area at one time. Bait the traps without setting them for several days to a week so that the rats become used to feeding at the traps. Then set the traps all at once. This is to ensure a large kill before the rats become trap shy and to interrupt their breeding cycle. It takes a lot of traps to implement this strategy so this is where the wooden snap trap shines because of its low cost.
You can bait your traps with items commonly found around the home. Homeowners often bait traps with foods such as bacon, nuts, candy bars and peanut butter. Peanut butter tends to be one of the most widely used and effective dates that can be found at home. No need to buy expensive commercial rat attractants.
After trapping as many rats as possible began to seal any and all access points into your home. Openings or cracks even as small as one quarter to one half an inch must be sealed. Stuffing copper wire mesh into the holes is a very effective way of sealing them. Follow that up with a construction type expanding foam or possibly a caulk to seal the mesh in place. Some people have had success using the copper mesh pots scrubbers found in the kitchen to seal the occasional opening. Heavy hardware cloth can be placed across vents and other larger openings. Just ensure that the holes in the mesh are small enough to keep rodents from crawling through. It is not necessary to spend lots of money but you do want to make sure that the materials you use to seal your home cannot be chewed through.
Make sure you remove all sources of food the rodents might use around your home. Do not leave pet food out, make sure trashcan lids are tight and any fruit or nuts on the ground from trees are removed. If you like to feed birds and have a rat problem you may need to stop that practice. Rats are very fond of eating birdseed! If you have to get rid of rats, making sure there is nothing for them to eat is vital.
Lastly, it is time to de-clutter in and around the home. Thin out any thick undergrowth and as much as possible, keep a relatively clear space all around the perimeter of the house. Rats like to hide in thick growth while chewing their way into your home. At the same time cutback any bushes or trees touching the home as the rodents use these to climb onto the roof and seek access into the home. This can all be accomplished with just some time and energy if you do it yourself.
You can get rid of rats around the home with a little money, a little sweat and some ingenuity. Apply the basics of rat control consistently and you can win the war against rats without spending a fortune.
About the Author
After battling rats in his attic and around his home for many years, Randy Parsley eventually won his battle against rodents. He shares his unique perspective in the form of honest reviews and information about rat control devices and methods at http://ratcontrolreviews.com.
The rat traps are basically used as one of the rodent control products. These rodent control devices can be used in all places where there are lots of problems caused by rats, it is essential to use the rodent control methods. These rodent control rat traps are basically used to trap the rats and mice and kill them slowly or instantly. These rodent control rat traps are basically constructed to stop mice breeding and to stop mice problems. These rat traps also help to stop mice population. It is not easier to catch mice and stop mice from making problems, so specific devices must be used to catch mice. These rat and mouse traps are made from metallic parts and require careful handling. These mouse traps require to be kept at far places away from the reach of children and pet animals. Some of the rodent control rats traps are the humane traps, snap traps, live catching mouse traps. Apart from these types of rat traps, there also exist the electronic rat traps. Let us discuss about the electronic rat traps.
The electronic rat traps do not require any sort of toxic and poisonous pesticides to be mixed with baits. These electronic rat traps also do not cause any sort of pollution in the environment. This rodent control electronic trap which can be used to stop mice breeding as well as stop mice breeding consists of a zigzag tunnel, four AA batteries, a green indicator light and two metal plates. All these equipments are equipped in the cabin. Let us now discuss about the way it works. The bait is placed inside the cabin and the smell produced by the bait attracts the rats to enter the tunnel. The bait is placed on the two metal plates. The metal plates are kept charged with the help of four AA batteries which are capable of exterminating up to fifty rats. As the rat enters the tunnel and when it tries to get the bait from the metal plates, it will be immediately destroyed because the metal plates deliver high voltage electrical charge. Thus the green indicator light installed on the top of the cabin will glow to indicate that a rat has been trapped and killed. The green indicator is capable of remaining on twenty four hours round the clock after the rat is being trapped. There is also a hinged door which can be opened to dispose off the killed rat to far off places without touching the corpse.
The advantages of using electronic rat traps are as follows. These rat traps do not cause any sort of dirt or horrible scene by killing them as compared to other rat traps. This rat trap is one of the eco-friendly products. This electronic rat traps can be easily installed in all places without the fear of kids and pet animals. The four batteries create the sufficient power to kill the rat. The twenty four hour green indicator help to show that the rat has been killed and glows till the killed rat has been disposed. Thus it does not produce any kind of air pollution. Apart from these, the electronic rat traps are available at affordable prices in the market.
About the Author
Author is an SEO and provide methods to repel and kill rats. To know more about stop mice and rodent control visit buyscram.com
How to catch a RAT
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[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] Can you rate my remove beast deck?
Monsters:20
Des Kangaroo x2 Big Koala x2 Behemoth The King of all animals Great Angus x3 Lycanthrope King Tiger Wanghu x2 Mad Dog of Darkness Bazoo the Soul-Eater x2 Prevent Rat Soul Tiger Lady Panther Enraged Battle Ox Boar Soldier Battle Ox
Spells:16
The Big March of Animals D.D.R. - Different Dimension Reincarnation Big Bang Shot Nobleman of Extermination Dark Core Soul Release Dimensional Fissure x2 Creature Swap Enemy Controller Nobleman of Crossout Brain Control Synthesis Spell Forest x2 Polymerization
Traps:10
Sakuretsu Armor Torrential Tribute Bottomless Trap Hole Nutrient Z Ultimate Offering Curse of Aging Return from the different dimension D.D. Dynamite Karma Cut Triggered Summon
This deck seems to work pretty slow. A couple good offense monsters should beef it up a bit. Lycanthrope seems like a waste to this deck. A Goblin Attack Force would work much better.
Manchester Pest Control Tips: The Top 6 Ways To Prevent Rat Infestations
Manchester pest control is an essential service today with the number of pests and subsequent infestations on the rise. One of the most common pests, and one of the most dreaded by business owners and homeowners alike, is the rat. Manchester pest control companies certainly have to deal with more and more rats, as are those in other areas of the country. However, there are plenty of things you can do to prevent rats becoming a problem in your property. In order to avoid calling the pest control Manchester brigade in, you first have to find out about how rats get into property in the first place. They have a very flexible bone structure, meaning that they can get through even the smallest of holes. They have been known to get through openings as small as half an inch in diameter. More worryingly still, they can climb and jump well. All of the above, when combined with the fact that they are opportunistic, mean that they are amongst the majority of cases dealt with by Manchester pest control. So what can you do to prevent a rat infestation? The 6 tips below will help: 1. Clear away any rubbish in your garden or around your property. Whether you have old furniture out there or piles of leaves, any items that can provide cover and protection will attract rats. 2. Maintain your garden, if you have one. Any overgrown shrubs, plants and trees will also provide rats with a haven in which they will thrive so it is only a matter of time until they find a way into your home. 3. Establish a perimeter around your garden. Using a border of gravel that is 2 feet in diameter will deter rats and prevent them from burrowing into the soil as well. 4. If you have a compost heap then contain it. Using compost bins is far more desirable than allowing a heap of potential food to build up. Manchester pest control also reports the same applies for compactors outside business premises. Keep the area clean and free from potential food. 5. Routinely check the wires and vents leading outside of the house or business premises because the loosening of such fixtures can provide rats with holes to squeeze through. If there are any holes then fill them as soon as you can. 6. Keep any doors shut whenever they are not manned. Rats will quite happily invite themselves indoors if and when the opportunity arises and an open door is the prime opportunity. So there you have it – a little about rats and the best 6 tips to help you in the fight against them. All of the above points will help you to keep rats out but if they do get in then Manchester pest control companies can provide the solution you need to get your premises free and clear of your rodent enemies. Although prevention is better than cure, you will always have an effective backup available just in case. About the Author
Pest Control Manchester wasp nest removal Treatments £29.50. All pest infestation dealt with. Ants, Bedbugs, Fleas, flies, Cockroach, Beetles, Rats, Mice, squirrels, Bird Control, rat control treatments . Want to know more about pest control come to http://www.youngspestcontrol.co.uk.
Rat shooting with Weihrauch HW 100 .177 12ftlbs (Humane vermin control) night vision by snypercat
[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] What is the best bait to use on rat traps? ?
The vector snapping kind of rat trap is what I will be using... I found out on where to place the traps but i have no idea what bait would be best to catch the rats... Thanks for your answer... Olivia
I am a self designated expert rat trapper, and I've tried all the odd ball stuff, gum drops- they wouldn't touch them, peanut butter- they licked the traps clean, and went to the next one. The very best is pieces of real cheese. They will not touch the cheap slices of store brand cheese, because they are merely cheese imitations. They prefer Kraft or Bordens sliced cheese.
[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] How much do rats usually cost at pet stores?
I need to know how much different kinds or rodents cost, plus small rabbits. This includes guinea pigs, gerbils, rats, mice, hamsters, small rabbits and any other rodent or small creature that pet shops sell. That way I can calculate how much it will cost to start my own rodent farming business. Please list which state the store is from and which store it is when you give me the price. Thank you.
small rodents cost about $4.00 to $20.00 rabbits and bigger rodents $25.00 to $250.00
Do You Need Exterminators In Los Angeles To Help Keep Your Home Healthy?
Hiring Exterminators To Perform An Attic Clean Out Will Do The Trick!
When is the last time you hired exterminatorsto inspect your attic?
Unfortunately, many people fail to consider the importance of hiring exterminators in Los Angeles to perform Attic Clean Outs in their homes. Yet, performing these clean outs is essential when it comes to keeping your home and your family healthy and safe.
Even if you think you have managed to get rid of the rats in your attic on your own, hiring exterminators to confirm that you are rat-free and remove leftover biological waste will ensure your home remains safe for your family.
Hiring exterminators to perform an Attic Clean Out is an essential part of caring for the health of your home. This is particularly true if you know you have experienced a rat infestation or if there is a possibility that rats may have made a home in your attic.
If your attic is not cleaned by a professional exterminator, a number of factors may contribute to the poor health of your home. Some of these include…
Rat Droppings
Dead Carcasses
Left Over Traps
Rat Urine
All of these accumulate over time in the attic, where temperatures can easily reach more than 150 degrees Fahrenheit beneath the California sun. Not only is the resulting smell quite offensive, but the heat combined with the waste also results in bacteria that can lead to a number of different health issues.
When you hire exterminators in Los Angeles to perform an Attic Clean Out, all of the leftover waste is removed so it can no longer serve as a home and breeding ground for bacteria. In addition, the exterminatorswill remove all of the infested insulation and replace it with new insulation. Of course, before installing the new insulation, the exterminatorsget rid of any live rodents that may still be in the attic while also blocking all entrances to the attic.
As a result, your rat infestation is taken care of while also removing all of the signs that they once lived in your home.
So, if you suspect that you have a rat infestation or if you had an infestation and think you have taken care of the problem, it is important to hire exterminators to make certain your attic is truly rat-free -- and free from rat waste. By doing so, you can avoid dealing with unpleasant smells while also keeping your home clean and free from potentially harmful bacteria.
About the Author
Locally owned and operated since 1994. We will provide you with excellent workmanship and pricing for all phases of your pest control needs. We provide services for residential, associations, commercial, and multi-family properties. We also offer NON-TOXIC treatments when possible(ORANGE OIL & FOAM), as well as preventative treatments including yearly maintenance plans, fumigation, escrow inspections, wood repair, and structural replacement. To learn more visit our website at www.AccuracyPlusCalifornia.com or call us TOLL FREE 888-675-0258!
Norway Rat Control, House Mouse Extermination, Rodent Removal, Pest Management, Boston MA
[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] Often various govts spend billions on eradication of rats. Why don't they spend so much to remove cockroaches?
professional courtesy. one cockroach does not want to kill another cockroach
Visualize yourself sleeping comfortably after a really hard day's work. You are caught up in a truly awesome#great} dream, mouth lolling open from tiredness. In between intakes of breath and the infrequent snore, you feel a little something plummeting on your face, then simply something will get into your mouth and you instantly fix awake, coughing and choking, breaking#ceasing#ruining} your calming sleep. Horror of horrors, you find out to your complete disgust that what you assumed was dust or what ever was really rat droppings! Eeeew! I wager you won't wish to have such an episode to happen to you.
There is always a particular need for these problems to be set under control, seeing as these issues are certainly not only prevalent in Florida, but worldwide. Businesses and homes don't seem to be all safe from the risks and damages connected with rodent infestation.
The must} for good quality rodent control and elimination is really a well-known issue in Florida, where house owners and business proprietors are at superior risk for infestation. The presence of rodents on an individual's roof goes well past the frequent rat control issue. The affliction risk nonwithstanding, the existence of roof rats can set off problems}} on housing and professional property. It is actually imperative to discover steps on how to keep roof rat infestations under control.
Rats are a big carrier of hazardous issues and a quantity of bacterial infections, among them the Hantavirus Pulmonary Syndrome, the plauge, Murine Typhus, Leptospirosis, Eosinophilic Meningitis, and Rat Bite Fever. The coterie of diseases are all very much destructive and have an impact any one irrespective of age or state of health, which is why preventing rat infestation must remain one of a homeowner's or business owner's major focus.
Assuming you have rodent control challenges, it should be easy to take on} diseases brought by the pests considering it really is simple to extend the bacteria taken by rats by their droppings or by them coming into contact with food. Rat bites aren't going to be the sole means to multiply illness. Apart from droppings, urine is additionally another really risky thing to come into contact with. If the pest infestation is not put under control, you will end up at potential risk for being infected with illnesses from the existence of roof rats. The ingestion of droppings, the contact of rat urine with food products or water, on skin even, and the inhalation of the fume from rat excretement is good enough to infect a person.
The removal of rat droppings and even any try at a thorough and quick termination of a rodent infestation might be unsafe, and really should be addressed by a coached and qualified Florida Pest Control consultant. The process of cleaning, decontamination, and termination is fast, trusted, and will verify advantageous for any business establishment or household.
About the Author
Know More About Rodent Control and lets all find out how we can control over them inside our households. Contact us for more details about Rodent Service
Imagine sleeping comfortably, drifting far from a very very nice dream, peaceful and with your mouth completely open from your day's tiredness. Now imagine getting up from your dream because some foreign things you still have no idea are dropping like rain on your face. Triple the terrible feeling after finding out that those things are actually some roof rat droppings! I really hope this won't happen to you!
There's a particular necessity of keeping those issues brought about by roof rats just below one's control. This has been a frequent concern not only in Florida but also throughout the planet. Business proprietors and homeowners are all not safe from the risks and harms generally linked with such kind of rodent infestation.
This roof rat problem would go well past what is viewed as average pest or rat control concern. A lot of the rodents known to man carry unspeakable illnesses and might wreak chaos on every commercial or residential property where they are able to infest, but most particularly, one should keep in mind that having control on those damn roof rats must be a top priority. Don't forget this: a roof rat problem, no matter how big or little it is, merits an immediate call to any pest management.
Because a roof rat is equivalent to a major health threat, having it in your business or especially in your home sweet home is really a humongous cause of alarm. These sorts of pests could bring lots of bacterial and viral infections which may include serious ones like Rat Bite Fever, Eosinophilic Meningitis, Leptospirosis, Murine Typhus, plague and Pulmonary Syndrome. With these mentioned health threats, the necessity to take action in a timely manner should be in one's checklist.
Of course, having a roof rat problem could affect anyone, so it is to be known that proper awareness and knowledge about such pests are essential. One should take note that it is much more only just a rat bite where the health issues could be spread. Coming to contact with these dangerous roof rat droppings is one thing you should not underestimate since it is a whole lot easier than what you could imagine. The toxic concentration of those bacteria which are totally infectious could be easily carried via the roof rat droppings as well as the urine. Once these roof rats are taken for granted, you might say bye-bye already to the safeness of your home or business seeing that a spot with roof rats abounding is far from safe at all. Roof rats are capable of taking over one's water and food sources and then leaving their own excrement behind for anyone unsuspecting like you and your family members to ingest.
Once your business or home becomes a subject to this health condition, the disease transmission is just a click of the hand. It's as simple as that. You can actually breathe in the dust debris that come from those roof rat poop or eat foodstuff with those little black poop. Such issue is even greater amplified once these awful rats would decide to make their own abode in your own air vents.
Which means, once a rat sighting has occurred, it is doubtlessly rational and smart enough to grant a professional pest service control a call in a timely manner!
About the Author
Know More About Rat Control and lets all find out how we can control over them inside our households. Contact us for more details about Rat Control
Rat problem - Up in Town feat. Joanna Lumley - BBC
[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] What happens if my dog got rat poison in its mouth but didn't swallow it?
Well my dog grabbed the bait of rat poison but I took it away before it could do anything else. Can my dog still die?
The same thing happened to me . I was worried so bad , but he hadn't bitten into it yet . That was over a month and a half ago and he's still kicking . Oh , and I guess it depends on your dogs size , so my dog is a mini schnauzer and he is still okay .
The Swimming Pool Q's - Rat Bait - 45rpm Earlier Works! 1979
Many different types of rat traps are available on the market today from live catch traps to traditional break-back traps.
The live catch traps on a whole tend to be cage traps. The rat is tempted into the cage with a bait (many types of bait will work from chocolate to cereals). The bait is placed onto the platform or hook (depending on the design), as the rat is feeding it will trigger the trap and the cage door will close trapping the rat inside.
Knowing your pests
The common rat - rattus norvegicus has been around since the early 18th century, these rats can be found in both urban and rural areas, they can be found both indoors and outdoors and often associated with sewer systems.
The common rat will reach sexual maturity at 8-12 weeks, the gestation period is 21-24 days, litter size on average is 6-11 with around 4-6 litters per year, and the weaning period is 3-4 weeks.
The average life span for the rat is around 1 year; it is likely that less than 5% of rats will survive more than 12 months.
Before starting trapping you will need to learn a bit about your pest, identify where they are living, feeding and travelling. Things to look for are droppings, smear marks (these are oily / dirty looking marks) these smear marks can be found along the rats run, around doors, skirting boards holes in the building fabric etc.
The rats droppings are around ½" long spindle and slightly banana looking in shape with pointed ends, they are a dark brown in colour and supple looking, after 3 days they will harden and lose their colour. Once you have identified the run the cage trap can be placed along this run but you have to take into account rats suffer from neophobia, this means that anything you put down for the rat he may well avoid for a good few days.
The trap needs to be checked every 24 hours so not to cause the trapped animal any further distress. Break-back traps and electronic traps are designed to kill the pest instantly.
The break-back trap is set off by the rat placing its paws on the baited platform thus setting off the trap and a spring loaded bar comes down on the rat breaking its back and killing it instantly, the electronic rat killer is a tunnel design, the rat will enter to feed from the bait placed within the devise and as the rats paws touch a pad inside the unit it is electrocuted and dies instantly.
These types of traps need to be placed as above along rat runs and again the neophobia will come into effect.
About the Author
Rat traps and cages are fast and effective ways of controlling your rat problem. Rat traps are available from PPC Supplies.
Few rodents are universally feared and reviled as the rat. Similar in shape to a mouse, they are a much larger rodent with a much more negative past. Rather than just being a nuisance, rats have been a health risk throughout the ages, spreading diseases, such as the plague to humans. Rat traps are generally designed to be lethal, as there is very little interest in relocating these potentially dangerous vermin to anywhere else, other than a shallow grave.
The average rat can grow up to 10 inches long and can easily weigh 1 pound. Although they are similar in shape to mice, by contrast, the average mouse only grows to be about 3 inches long and usually weighs less than an ounce. Because of their large size, a rat trap will be much larger and more powerful than a mouse trap. The common spring loaded bar rat trap is strong enough to snap the neck or spine of a rat and is also strong enough to break a human finger. Household pets can also become injured by a rat trap, as the force of the spring may be lethal to cats and small dogs. For this reason, extreme caution should be used when handling a rat trap.
There are other types of rat traps on the market as well, that are less dangerous to handle for people. Many rat traps are cages with doors that close behind the rat when the rat enters the trap. These traps are usually baited with food, such as bread or cheese, which is meant to entice the rat to enter the trap. Because of the large size of a rat, these traps are also capable of capturing other small animals, such as cats, small breeds of dog and rabbits. If you have these types of pets around, it is extremely important that you not poison the food, for risk of poisoning a pet. One of the newest kinds of rat traps on the market is the electronic rat trap. This trap has certain advantages over other types in that it is much safer for people and a single trap can be used to catch and kill many rats.
Although some people do keep rats as pets, most of the time a rat is an unwelcome visitor in your home. If you have a rat problem, the chances are you may need more than just a rat trap. If there are multiple rats in your home, you may want to call in an expert, who can get these dangerous rodents out of your home. With the risk of disease that they carry with them, it is never too soon to get them out of your house!
[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] whats the best way to catch a rat?
a rat not a mouse with out killing it? ive looked all over 4 a humain mouse trap that is big enough 4 a rat but i cant seem to find one anywhere! so whats a good way to catch a rat but not hurting him in anyway? and ALL poison is out of the question cuz i have 3 dogs that eat EVERYTHING.
Call your local humane society or animal control center. They usually have no-kill traps that you can borrow, like this one
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[simpleaffiliate source="chitika" results="0"][/simpleaffiliate] what is the title of a film where two guys are pest control officers and do a robbery and go on the run?
with a car with a huge rat on the roof for pest control,there is a bar scene where a snake gets shot and a woman goes "oh my god they killed Gus!" and its a bit of a zany comedy.i think it was made in the mid 80-90's and was last shown in the mid 90s on bbc one in the uk.is it called "the cops are robbers" i looked it up but the pest control guys bit doesn't tie in with this--any idea what this title of the film/movies is please and who acted in it?
Environ Pest Control:Giant rat caught in Fulham,London,Engl
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Laser beam profiling instruments measure the following quantities:
Beam width: There are over five definitions of beam width.
Beam quality: Quantified by the beam quality parameter, M2.
Beam divergence: This is a measure of the spreading of the beam with distance.
Beam profile: A beam profile is the 2D intensity plot of a beam at a given location along the beam path. A Gaussian or flat-top profile is often desired. The beam profile indicates nuisance high-order spatial modes in a laser cavity as well as hot spots in the beam.
Beam astigmatism: The beam is astigmatic when the vertical and horizontal parts of the beam focus in different locations along the beam path.
Beam wander or jitter: The amount that the centroid or peak value of the beam profile moves with time.
Instruments and techniques were developed to obtain the beam characteristics listed above. These include:
Camera techniques: These include the direct illumination of a camera sensor. The maximum spot size that will fit onto a CCD sensor is on the order of 10 mm. Alternatively, illuminating a flat diffuse surface with the laser and imaging the light onto a CCD with a lens allows profiling of larger-diameter beams. Viewing lasers off diffuse surfaces is excellent for large beam widths but requires a diffuse surface that has uniform reflectivity (<1% variation) over the illuminated surface.
Knife-edge technique: A spinning blade or slit cuts the laser beam before detection by a power meter. The power meter measures the intensity as a function of time. By taking the integrated intensity profiles in a number of cuts, the original beam profile can be reconstructed using algorithms developed for tomography. This usually does not work for pulsed lasers, and does not provide a true 2D beam profile, but it does have excellent resolution, in some cases <1 m.
Historical techniques: These include the use of photographic plates and burn plates. For example, high-power carbon dioxide lasers were profiled by observing slow burns into acrylate blocks.
As of 2002[update], commercial knife-edge measurement systems cost $5,000$12,000 USD and CCD beam profilers cost $4,0009,000 USD. The cost of CCD beam profilers has come down in recent years, primarily driven by lower silicon CCD sensor costs, and as of 2008[update] they can be found for less than $1000 USD.
Applications
The applications of laser beam profiling include:
Laser cutting: A laser with an elliptical beam profile has a wider cut along one direction than along the other. The width of the beam influences the edges of the cut. A narrower beam width yields high fluence and ionizes, rather than melts, the machined part. Ionized edges are cleaner and have less knurling than melted edges.
Nonlinear optics: Frequency conversion efficiency in nonlinear optical materials is proportional to the square (sometimes cubed or more) of the input light intensity. Therefore, to get efficient frequency conversion, the input beam waist must be as small as possible. A beam profiler can help minimize the beam waist in the nonlinear crystal.
Alignment: Beam profilers align beams with orders of magnitude better angular accuracy than irises.
Laser monitoring: It is often necessary to monitor the laser output to see whether the beam profile changes after long hours of operation. Maintaining a particular beam shape is critical for adaptive optics, nonlinear optics, and laser-to-fiber delivery. In addition, laser status can be measured by imaging the emitters of a pump diode laser bar and counting the number of emitters that have failed or by placing several beam profilers at various points along a laser amplifier chain.
Laser and laser amplifier development: Thermal relaxation in pulse-pumped amplifiers causes temporal and spatial variations in the gain crystal, effectively distorting the beam profile of the amplified light. A beam profiler placed at the output of the amplifier yields a wealth of information about transient thermal effects in the crystal. By adjusting the pump current to the amplifier and tuning the input power level, the output beam profile can be optimized in real-time.
Far-field measurement: It is important to know the beam profile of a laser for laser radar or free-space optical communications at long distances, the so-called ar-field. The width of the beam in its far-field determines the amount of energy collected by a communications receiver and the amount of energy incident on the ladar target. Measuring the far-field beam profile directly is often impossible in a laboratory because of the long path length required. A lens, on the other hand, transforms the beam so that the far-field occurs near its focus. A beam profiler placed near the focus of the lens measures the far-field beam profile in significantly less benchtop space.
Education: Beam profilers can be used for student laboratories to verify diffraction theories and test the Fraunhofer or Fresnel diffraction integral approximations. Other student laboratory ideas include using a beam profiler to measure Poisson spot of an opaque disk and to map out the Airy disk diffraction pattern of a clear disk.
Measurements
Beam width
Main article: Beam diameter
The beam width is the single most important characteristic of a laser beam profile. At least five definitions of beam width are in common use: D4, 10/90 or 20/80 knife-edge, 1/e2, FWHM, and D86. The D4 beam width is the ISO standard definition and the measurement of the M beam quality parameter requires the measurement of the D4 widths. The other definitions provide complementary information to the D4 and are used in different circumstances. The choice of definition can have a large effect on the beam width number obtained, and it is important to use the correct method for any given application. The D4 and knife-edge widths are sensitive to background noise on the detector, while the 1/e2 and FWHM widths are not. The fraction of total beam power encompassed by the beam width depends on which definition is used.
D4 or second moment width
D4 is shorthand for the diameter that is 4 times , where is the standard deviation of the horizontal or vertical marginal distribution. Mathematically, the D4 beam width in the x-dimension for the beam profile I(x,y) is expressed as
,
where
is the centroid of the beam profile in the x-direction. The wings of the beam profile influence the D4 value more than the center of the beam profile since the wings of the marginal distribution are weighted by the square of its distance, x2, from the center of the beam. If the beam does not fill more than a third of the beam profiler sensor area, then there will be a significant number of pixels at the edges of the sensor that register a small baseline value (the background value). If the baseline value is large or if it is not subtracted out of the image, then the computed D4 value will be larger than the actual value because the baseline value near the edges of the sensor are weighted in the D4 integral by x2. Therefore, baseline subtraction is necessary for accurate D4 measurements. The baseline is easily measured by recording the average value for each pixel when the sensor is not illuminated. The D4 width, unlike the FWHM and 1/e2 widths, is meaningful for multimodal marginal distributions that is, beam profiles with multiple peaks but requires careful subtraction of the baseline for accurate results. The D4 is the ISO international standard definition for beam width.
Knife-edge width
Before the advent of the CCD beam profiler, the beam width was estimated using the knife-edge technique. The technique is as follows: slice a laser beam with a razor and measure the power of the clipped beam as a function of the razor position. The measured curve is the integral of the marginal distribution, and starts at the total beam power and decreases monotonically to zero power. The width of the beam is defined as either the distance between the points of the measured curve that are 10% and 90% (or 20% and 80%) of the maximum value. If the baseline value is small or subtracted out, the knife-edge beam width always corresponds to 60%, in the case of 20/80, or 80%, in the case of 10/90, of the total beam power no matter what the beam profile. On the other hand, the D4, 1/e2, and FWHM widths encompass fractions of power that are beam-shape dependent. Therefore, the 10/90 or 20/80 knife-edge width is a useful metric when the user wishes to be sure that the width encompasses a fixed fraction of total beam power. Most CCD beam-profiler software can compute the knife-edge width numerically.
1/e2 width
The 1/e2 width is equal to the distance between the two points on the marginal distribution that are 1/e2 = 0.135 times the maximum value. If there are more than 2 points that are 1/e2 times the maximum value, then the two points closest to the maximum are chosen. The 1/e2 width only depends on 3 points on the marginal distribution, unlike D4 and knife-edge widths that depend on the integral of the marginal distribution. 1/e2 width measurements are noisier than D4 width measurements for each collected CCD frame. For multimodal marginal distributions (a beam profile with multiple peaks), the 1/e2 width usually does not yield a meaningful value and can grossly underestimate of the inherent width of the beam. For multimodal distributions, a D4 width would be a better choice.
The American National Standard Z136.1-2007 for Safe Use of Lasers (p.6) defines the beam diameter as the distance between diametrically opposed points in that cross-section of a beam where the power per unit area is 1/e (0.368) times that of the peak power per unit area. This is the beam diameter definition that is used for computing the maximum permissible exposure to a laser beam. In addition, the Federal Aviation Administration also uses the 1/e definition for laser safety calculations in FAA Order 7400.2F, "Procedures for Handling Airspace Matters," February 16, 2006, p. 29-1-2.
D86 width
The D86 width is defined as the diameter of the circle that is centered at the centroid of the beam profile and contains 86% of the beam power. The solution for D86 is found by computing the area of increasingly larger circles around the centroid until the area contains 0.86 of the total power. Unlike the previous beam width definitions, the D86 width is not derived from marginal distributions. The strange percentage of 86, rather than 50, 80, or 90, is chosen because a circular Gaussian beam profile integrated down to 1/e2 of its peak value contains 86% of its total power. The D86 width is often used in applications that are concerned with knowing exactly how much power is in a given area. For example, high-energy laser weapons and ladars are two applications that require precise knowledge of how much transmitted power actually illuminates the target.
Beam quality
Beam quality parameter, M2
Main article: Beam parameter product
The M2 parameter is a measure of beam quality; a low M2 value indicates good beam quality and ability to be focused to a tight spot. The value M is equal to the ratio of the beam angle of divergence to that of a Gaussian beam with the same D4 waist width. Since the Gaussian beam diverges more slowly than any other beam shape, the M2 parameter is always greater than or equal to one. Other definitions of beam quality have been used in the past, but the one using second moment widths is most commonly accepted.
Beam quality is important in many applications. In fiber-optic communications beams with an M2 close to 1 are required for coupling to single-mode optical fiber. Laser machine shops care a lot about the M2 parameter of their lasers because the beams will focus to an area that is M2 times larger than that of a Gaussian beam with the same wavelength and D4 waist width; in other words, the fluence scales as 1/M2. The general rule of thumb is that M2 increases as the laser power increases. It is difficult to obtain excellent beam quality and high average power (100 W to kWs) due to thermal lensing in the laser gain medium.
The M2 parameter is determined experimentally as follows:
Measure the D4 widths at 5 axial positions near the beam waist (the location where the beam is narrowest).
Measure the D4 widths at 5 axial positions at least one Rayleigh length away from the waist.
Fit the 10 measured data points to , where 2(z) is the second moment of the distribution in the x or y direction (see section on D4 beam width), and z0 is the location of the beam waist with second moment width of 20. Fitting the 10 data points yields M2, z0, and 0. Siegman showed that all beam profiles Gaussian, flat top, TEMXY, or any shape must follow the equation above provided that the beam radius uses the D4 definition of the beam width. Using the 10/90 knife-edge, the D86, or the FWHM widths does not work.
Complete E-field beam profiling
Beam profilers measure the intensity, |E-field|2, of the laser beam profile but do not yield any information about the phase of the E-field. To completely characterize the E-field at a given plane, both the phase and amplitude profiles must be known. The real and imaginary parts of the electric field can be characterized using two CCD beam profilers that sample the beam at two separate propagation planes, with the application of a phase recovery algorithm to the captured data. The benefit of completely characterizing the E-field in one plane is that the E-field profile can be computed for any other plane with diffraction theory.
Power-in-the-bucket or Strehl definition of beam quality
The M2 parameter is not the whole story in specifying beam quality. A low M2 only implies that the second moment of the beam profile expands slowly. Nevertheless, two beams with the same M2 may not have the same fraction of delivered power in a given area. Power-in-the-bucket and Strehl ratio are two attempts to define beam quality as a function of how much power is delivered to a given area. Unfortunately, there is no standard bucket size (D86 width, Gaussian beam width, Airy disk nulls, etc.) or bucket shape (circular, rectangular, etc.) and there is no standard beam to compare for the Strehl ratio. Therefore, these definitions must always be specified before a number is given and it presents much difficulty when trying to compare lasers. There is also no simple conversion between M2, power-in-the-bucket, and Strehl ratio. The Strehl ratio, for example, has been defined as the ratio of the peak focal intensities in the aberrated and ideal point spread functions. In other cases, it has been defined as the ratio between the peak intensity of an image divided by the peak intensity of a diffraction-limited image with the same total flux. Since there are many ways power-in-the-bucket and Strehl ratio have been defined in the literature, the recommendation is to stick with the ISO-standard M2 definition for the beam quality parameter and be aware that a Strehl ratio of 0.8, for example, does not mean anything unless the Strehl ratio is accompanied by a definition.
Beam divergence
Main article: Beam divergence
The beam divergence of a laser beam is a measure for how fast the beam expands far from the beam waist. It is usually defined as the derivative of the beam radius with respect to the axial position in the far field, i.e., in a distance from the beam waist which is much larger than the Rayleigh length. This definition yields a divergence half-angle. (Sometimes, full angles are used in the literature; these are twice as large.) For a diffraction-limited Gaussian beam, the beam divergence is /(w0), where is the wavelength (in the medium) and w0 the beam radius (radius with 1/e2 intensity) at the beam waist. A large beam divergence for a given beam radius corresponds to poor beam quality. A low beam divergence can be important for applications such as pointing or free-space optical communications. Beams with very small divergence, i.e., with approximately constant beam radius over significant propagation distances, are called collimated beams. For the measurement of beam divergence, one usually measures the beam radius at different positions, using e.g. a beam profiler. It is also possible to derive the beam divergence from the complex amplitude profile of the beam in a single plane: spatial Fourier transforms deliver the distribution of transverse spatial frequencies, which are directly related to propagation angles. See US Laser Corps application note for a tutorial on how to measure the laser beam divergence with a lens and CCD camera.
Beam astigmatism
See also: Astigmatism
Astigmatism in a laser beam occurs when the horizontal and vertical cross sections of the beam focus at different locations along the beam path. Astigmatism can be corrected with a pair of cylindrical lenses. The metric for astigmatism is the power of cylindrical lens needed to bring the focuses of the horizontal and vertical cross sections together. Astigmatism is caused by:
Thermal lensing in Nd:YAG slab amplifiers. A slab that is sandwiched between two metal heat sinks will have a temperature gradient between the heat sinks. The thermal gradient causes an index of refraction gradient that is very similar to a cylindrical lens. The cylindrical lensing caused by the amplifier will make the beam astigmatic.
Unmatched cylindrical lenses or error in placement of these optics.
Propagation through a nonlinear uniaxial crystal (common in nonlinear optic crystals). The x- and y-polarized E-fields experience different refractive indices.
Not propagating through the center of a spherical lens or mirror.
Astigmatism can easily be characterized by a CCD beam profiler by observing where the x and y beam waists occur as the profiler is translated along the beam path.
Beam wander or jitter
Every laser beam wanders and jitters albeit a small amount. The typical kinematic tip-tilt mount drifts by around 100 rad per day in a laboratory environment (vibration isolation via optical table, constant temperature and pressure, and no sunlight that causes parts to heat). A laser beam incident upon this mirror will be translated by 100 m at a range of 1000 km. This could make the difference between hitting or not hitting a communications satellite from Earth. Hence, there is a lot of interest in characterizing the beam wander (slow time scale) or jitter (fast time scale) of a laser beam. The beam wander and jitter can be measured by tracking the centroid or peak of the beam on a CCD beam profiler. The CCD frame rate is typically 30 frames per second and therefore can capture beam jitter that is slower than 30 Hz it can see fast vibrations due to one voice, 60 Hz fan motor hum, or other sources of fast vibrations. Fortunately, this is usually not a great concern for most laboratory laser systems and the frame rates of CCDs are fast enough to capture the beam wander over the bandwidth that contains the greatest noise power. A typical beam wander measurement involves tracking the centroid of the beam over several minutes. The rms deviation of the centroid data gives a clear picture of the laser beam pointing stability. The integration time of the beam jitter measurement should always accompany the computed rms value. Even though the pixel resolution of a camera may be several micrometres, sub-pixel centroid resolution (possibly tens of nanometer resolution) is attained when the signal to noise ratio is good and the beam fills most of the CCD active area.
Beam wander is caused by:
Slow thermalization of the laser. Laser manufacturers usually have a warm-up specification to allow the laser to drift to an equilibrium after startup.
Tip-tilt and optical mount drift caused by thermal gradients, pressure, and loosening of springs.
Non-rigidly mounted optics by accident of course!
Vibration due to fans, people walking/sneezing/breathing, water pumps, and movement of vehicles outside the laboratory.
Misrepresentation of beam profiler measurements for laser systems
It is to most laser manufacturers' advantage to present specifications in a way that shows their product in the best light, even if this involves misleading the customer. Laser performance specifications can be clarified by asking questions such as:
Is the specification typical or worst-case performance?
What beam width definition was used?
Is the M2 parameter for both vertical and horizontal cross sections, or just for the better cross section?
Was M2 measured using the ISO-standard technique or some other way e.g. power in the bucket.
Over how long was the data taken to come up with the specified rms beam jitter. (RMS beam jitter gets worse as the measurement interval increases.) What was the laser environment (optical table, etc.)?
What is the warm-up time needed to achieve the specified M2, beam width, divergence, astigmatism, and jitter?
Techniques
Beam profilers generally fall into two classes: the first uses a simple photodetector behind an aperture which is scanned over the beam. The second class uses a camera to image the beam.
Scanning-aperture techniques
The most common scanning aperture techniques are the knife-edge technique and the scanning-slit profiler. The former chops the beam with a knife and measures the transmitted power as the blade cuts through the beam. The measured intensity versus knife position yields a curve that is the integrated beam intensity in one direction. By measuring the intensity curve for several directions, the original beam profile can be reconstructed using algorithms developed for x-ray tomography.
Scanning-slit profilers use a narrow slit instead of a single knife edge. In this case, the intensity is integrated over the slit width. The resulting measurement is equivalent to the original cross section convolved with the profile of the slit.
These techniques can measure very small spot sizes down to 1 m, and can be used to directly measure high power beams. They do not offer continuous readout, although repetition rates as high as ten hertz can be achieved. Also, the profiles give integrated intensities in the x and y directions and not the actual 2D spatial profile (integrating intensities can be hard to interpret for complicated beam profiles). They do not generally work for pulsed laser sources, because of the extra complexity of synchronizing the motion of the aperture and the laser pulses.[citation needed]
CCD camera technique
The CCD camera technique is simple: attenuate and shine a laser onto a CCD and measure the beam profile directly. It is for this reason that the camera technique is the most popular method for laser beam profiling. The most popular cameras used are silicon CCDs that have sensor diameters that range up to 25 mm (1 inch) and pixel sizes down to a few micrometres. These cameras are also sensitive to a broad range of wavelengths, from deep UV, 200 nm, to near infrared, 1100 nm; this range of wavelengths encompass a broad range of laser gain media. The advantages of the CCD camera technique are:
It captures the 2D beam profile in real-time
Software typically displays critical beam metrics, such as D4 width, in real-time
Sensitive CCD detectors can capture the beam profiles of weak lasers
Resolution down to about 5 m
CCD cameras with trigger inputs can be used to capture beam profiles of low-duty-cycle pulsed lasers
CCD have broad wavelength sensitivities from 200 to 1100 nm
The disadvantages of the CCD camera technique are that attenuation is required for high power lasers, and CCD sensor size limited to about 1 inch.
Baseline subtraction for D4 width measurements
The D4 width is sensitive to the beam energy or noise in the tail of the pulse because the pixels that are far from the beam centroid contribute to the D4 width as the distance squared. To reduce the error in the D4 width estimate, the baseline pixel values are subtracted from the measured signal. The baseline values for the pixels are measured by recording the values of the CCD pixels with no incident light. The finite value is due to dark current, readout noise, and other noise sources. For shot-noise-limited noise sources, baseline subtraction improves the D4 width estimate as , where N is the number of pixels in the wings. Without baseline subtraction, the D4 width is overestimated.
Averaging to get better measurements
Averaging consecutive CCD images yields a cleaner profile and removes both CCD imager noise and laser beam intensity fluctuations. The signal-to-noise-ratio (SNR) of a pixel for a beam profile is defined as the mean value of the pixel divided by its root-mean-square (rms) value. The SNR improves as square root of the number of captured frames for shot noise processes dark current noise, readout noise, and Poissonian detection noise. So, for example, increasing the number of averages by a factor of 100 smooths out the beam profile by a factor of 10.
Attenuation techniques
Since CCD sensors are highly sensitive, attenuation is almost always needed for proper beam profiling. For example, 40 dB (ND 4 or 10-4) of attenuation is typical for a milliwatt HeNe laser. Proper attenuation has the following properties:
It does not result in multiple reflections leaving a ghost image on the CCD sensor
It does not distort the wavefront and will be an optical element with sufficient optical flatness (less than one tenth of a wavelength)
It can handle the required optical power
For laser beam profiling with CCD sensors, typically two types of attenuators are used: neutral density filters, and wedges or thick optical flats.
Neutral density filters
Main article: Neutral density filter
Neutral density (ND) filters come in two types: absorptive and reflective. Absorptive filters (for example made of Schott 1234 glass) are for lower-power applications that involve up to about 100 mW average power. Above those power levels, one risks melting the filter. Absorptive filter attenuation values are valid for the visible spectrum (500700 nm) and are not valid outside of that spectral region. Typically, one can expect about 10% variation of the attenuation across a 2-inch (51 mm) ND filter. The attenuation values of ND filters are specified logarithmically. A ND 3 filter transmits 10-3 of the incident beam power. Placing the largest attenuator last before the CCD sensor will result in the best rejection of ghost images due to multiple reflections. Reflective filters are made with a thin metallic coating and hence operate over a larger bandwidth. An ND 3 metallic filter will be good over 2002000 nm. The attenuation will rapidly increase outside this spectral region. These filters reflect rather than absorb the incident power, and hence can handle higher input powers. These filters work fine to about 5 W average power (over about 1 cm2 illumination area) before heating causes them to crack. Since these filters reflect light, one must be careful when stacking multiple ND filters, since multiple reflections among the filters will cause a ghost image to interfere with the original beam profile. One way to mitigate this problem is by tilting the ND filter stack. Assuming that the absorption of the metallic ND filter is negligible, the order of the ND filter stack doesn matter, as it does for the absorptive filters.
Optical wedges
Optical wedges and reflections from uncoated optical glass surfaces are used to attenuate high power laser beams. About 4% is reflected from the air/glass interface and several wedges can be used to greatly attenuate the beam to levels that can be attenuated with ND filters. The angle of the wedge is typically selected so that the second reflection from the surface does not hit the active area of the CCD. The farther the CCD is from the wedge, the smaller the angle required. Wedges have the disadvantage of both translating and bending the beam direction paths will no longer lie on convenient rectangular coordinates. Rather than using a wedge, an optical-quality thick glass plate tilted to the beam can also work actually, this is the same as a wedge with a 0 angle. The thick glass will translate the beam but it will not change the angle of the output beam. The glass must be thick enough so that the secondary reflection does not illuminate the active area of the CCD. The Fresnel reflection of a beam from a glass plate is different for the s- and p-polarizations (s is parallel to the surface of the glass, and p is perpendicular to s) and changes as a function of angle of incidence keep this in mind if you expect that the two polarizations have different beam profiles. To prevent distortion of the beam profile, the glass should be of optical quality surface flatness of /10 (=633 nm) and scratch-dig of 40-20 or better. A half-wave plate followed by a polarizing beam splitter form a variable attenuator and this combination is often used in optical systems. The variable attenuator made in this fashion is not recommended for attenuation for beam profiling applications because: (1) the beam profile in the two orthogonal polarizations may be different, and (2) the polarization beam cube may have a low optical damage threshold value. Inexpensive cube polarizers are formed by cementing two right angle prisms together. The glue does not stand up well to high powers the intensity should be kept under 500 mW/mm2. Single-element polarizers are recommended for high powers.
Optimal beam size on the CCD detector
There are two competing requirements that determine the optimal beam size on the CCD detector. One requirement is that the entire energy or as much of it as possible of the laser beam is incident on the CCD sensor. This would imply that we should focus all the energy in the center of the active region in as small a spot as possible using only a few of the central pixels to ensure that the tails of the beam are captured by the outer pixels. This is one extreme. The second requirement is that we need to adequately sample the beam profile shape. As a general rule of thumb, we want at least 10 pixels across the area that encompasses most, say 80%, of the energy in the beam. Therefore, there is no hard and fast rule to select the optimal beam size. As long as the CCD sensor captures over 90% of the beam energy and has at least 10 pixels across it, the beam width measurements will have some accuracy.
Pixel size and number of pixels
The larger the CCD sensor, the larger the size of beam that can be profiled. Sometimes this comes at the cost of larger pixel sizes. Small pixels sizes are desired for observing focused beams. A CCD with many megapixels is not always better than a smaller array since readout times on the computer can be uncomfortably long. Reading out the array in real-time is essential for any tweaking or optimization of the laser profile.
Far-field beam profiler
A far-field beam profiler is nothing more than profiling the beam at the focus of a lens. This plane is sometimes called the Fourier plane and is the profile that one would see if the beam propagated very far away. The beam at the Fourier plane is the Fourier transform of the input field. Care must be taken in setting up a far-field measurement. The focused spot size must be large enough to span across several pixels. The spot size is approximately f/D, where f is the focal length of the lens, is the wavelength of the light, and D is the diameter of the collimated beam incident upon the lens. For example, a helium-neon laser (633 nm) with 1 mm beam diameter would focus to a 317 m spot with a 500 mm lens. A laser beam profiler with a 5.6 m pixel size would adequately sample the spot at 56 locations.
Special applications
The prohibitive costs of CCD laser beam profilers in the past have given way to low-cost beam profilers. Low-cost beam profilers have opened up a number of new applications: replacing irises for super-accurate alignment and simultaneous multiple port monitoring of laser systems.
Iris replacement with microradian alignment accuracy
In the past, alignment of laser beams was done with irises. Two irises uniquely defined a beam path; the farther apart the irises and the smaller the iris holes, the better the path was defined that is, only a few light rays could be drawn through both irises. The smallest aperture that an iris can define is about 0.8 mm. In comparison, the centroid of a laser beam can be determined to sub-micrometre accuracy with a laser beam profiler. The laser beam profiler's effective aperture size is three orders of magnitude smaller than that of an iris. Consequently, the ability to define an optical path is 1000 times better when using beam profilers over irises. Applications that need microradian alignment accuracies include earth-to-space communications, earth-to-space ladar, master oscillator to power oscillator alignment, and multi-pass amplifiers.
Simultaneous multiple port monitoring of laser system
Experimental laser systems benefit from the use of multiple laser beam profilers to characterize the pump beam, the output beam, and the beam shape at intermediate locations in the laser system, for example, after a Kerr-lens modelocker. Changes in the pump laser beam profile indicate the health of the pump laser, which laser modes are excited in the gain crystal, and also determine whether the laser is warmed up by locating the centroid of the beam relative to the breadboard. The output beam profile is often a strong function of pump power due to thermo-optical effects in the gain medium.
References
^ R. Bolton, "Give your laser beam a checkup," Photonics Spectra, June 2002. Table 1.
^ a b ISO 11146-1:2005(E), "Lasers and laser-related equipment Test methods for laser beam widths, divergence angles and beam propagation ratios Part 1: Stigmatic and simple astigmatic beams."
^ ISO 11146-2:2005(E), "Lasers and laser-related equipment Test methods for laser beam widths, divergence angles and beam propagation ratios Part 2: General astigmatic beams."
^ ISO 11146-1:2005(E), "Lasers and laser-related equipment Test methods for laser beam widths, divergence angles and beam propagation ratios Part 3: Intrinsic and geometrical laser beam classification, propagation and details of test methods."
^ A. E. Siegman, "How to (Maybe) Measure Laser Beam Quality," Tutorial presentation at the Optical Society of America Annual Meeting Long Beach, California, October 1997.
^ A. E. Siegman, "How to (Maybe) Measure Laser Beam Quality," Tutorial presentation at the Optical Society of America Annual Meeting Long Beach, California, October 1997, p.9.
^ M. Born and E. Wolf, Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, 6th edition, Cambridge University Press, 1997.
^ Strehl meter W.M. Keck Observatory.
^ Measuring laser beam divergence US Laser Corps application note
^ Ankron. "Technical Note 5: How to measure beam jitter with nanometer accuracy using a CCD sensor with 5.6 m pixel size".
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Larvicidal activity of the weed plant Parthenium hysterophous L (compositae) against Aedes aegypti and Culex quinquefasciatus
INTRODUCTION
Mosquitoes are responsible for more diseases than any other group of arthropods. It is observed at the elevations of 5500 meters and minus situated at depth of 1250 meters below the sea level. Two important vector species of mosquitoes such as Aedes aegypti and Culex quinquefasciatus are selected for the present study. A. aegypti is the principal vector of Dengue fever and dengue haemorrhagic fever and it is reported to infect more than 100 million people every year in more than 110 countries in the tropics (Halstead, 2000). C. quinquefasciatus is the vector of West Nile Virus which causes encephalitis and meningities which is known to affect the brain tissues, finally resulting in permanent neurological damage. The most suitable remedy for the problems is to control their population and ever increasing use of chemicals to control mosquitoes was found to accumulate in the food chain, residual effect, high cost, environmental pollution and can also cause serious toxic hazards to humans, animals and other non-target creatures and developing resistance to conventional insecticides in many mosquito species have reviewed great interest in exploiting the vector control potential of natural origins. Pesticide exposure among humans has been linked to immune dysfunction, various forms of cancer and birth defects (Bounias, 2003). All these factors led to search for safer and more compatible alternatives to combat these problems, among which natural products, especially plant derived called botanicals are now emerging as a viable component of Integrated Pest Management (IPM) (Jeyabalan et al, 2003). Apart from neem, various other plant species have also shown promising pest controlling properties. These categories of pesticides are known as biopesticides (Mulla, 1994).
P. hysterophous is known as congress weed, carrot weed, star weed, feverweed, white top, chatak chandani, bitter weed, ramphool, garghsas. Parthenium is also reported as promising remedy against hepatic amoebiasis (Sharma & Bhutani, 1988). In the present study, an attempt has been made to record the larvicidal activity of leaf extracts of P.hysterophous L (Compositae) against A. aegypti and C. quinquefasciatus.
MATERIALS AND METHODS
The eggs of A. aegypti and C. quinquefasciatus were procured from the research laboratory of National Institute of Communicable Disease (NICD), at Mettupalayam, Coimbatore District, Tamilnadu (India) and it was maintained in sterilized containers with unchlorinated tap water (18cm diameter X 19 cm height) in laboratory conditions (29±20 C). The eggs and larvae obtained from stock were used for the experiments. Freshly hatched larvae were collected and maintained in separate containers with unchlorinated tap water and dog biscuit with yeast (2:1 ratio) was given as the source of food. Water was changed alternate days. The leaves of P. hysterophous were collected from nearby college campus and brought to the laboratory. The leaves were thoroughly washed with tap water and were dried under shade at room temperature (29 ± 20 C) for about 20 days. The completely dried leaves were powdered and sieved to get fine powder. The powdered leaves 100 gms were extracted separately with 300ml, hexane and acetone by using the Soxhlet apparatus for 8 hours, (Vogel, 1978). The extracts were concentrated using a vacuum evaporator at 450C under low pressure. After complete evaporation of the solvent the concentrated extract was collected and stored in a refrigerator for further experiments. From this stock, 1 gm of residue was dissolved in 100ml respective solvents and kept as a stock solution. This stock solution was used to prepare the desired concentrations of the extracts for exposure of mosquito larvae. The fourth instar larvae and pupae of both C. quinquefasciatus and A. aegypti were used for treatment experiments in the present study. At each tested concentrations 4 trails were made and controls were maintained (using respective solvents) along with the experiment. Mortality in control was negligible in calculation. The percentage of mortality was corrected by Abbot’s formula (1925). The data were subjected to probit analysis (Finney, 1971).
RESULTS AND DISCUSSIONS
The present study on the plant extracts expressed the presence of larvicidaland pupicidal activity of P. hysterophous on A. aegypti and C. quinquefasciatus. Mortality values of larvae and pupae treated with different concentrations of hexane and acetone extracts were ranging from 20-100ppm, 30-150ppm in Aedes and 10-50ppm, 60-100ppm in Culex of leaf extract of P. hysterophous .Based on the probit analysis the 24 hr LC50 of the leaf extract of P. hysterophous for third instar larvae and pupae for A. aegypti and C. quinquefasciatus against hexane extracts were 47.69, 52.15, 25.48, 29.05ppm and LC90 values were 81.79, 86.93, 45.14, 50.11ppm respectively. In acetone extract the LC50 values of the both species (third instar larvae and pupae) were 72.34, 78.54, 70.01, 74.33ppm and LC90 values were 140.54, 150.55, 93.97 and 101.58ppm respectively. In this experiment C .quinquefasciatus was more susceptible than A. aegypti. Among the hexane and acetone the highest larval and pupal mortality found in hexane extract in both the species. A. aegypti is commonly used in insecticide screening trails because it is usually less susceptible and easy to colonize in the laboratory (Shaalan et al., 2005).
The result of the present study was comparable to that of previous studies. Pizzaro et al (1999) were reported the activity of the saponine fraction of Agave sisalana and estimate the LC50 and LC90 values against 3rd instar larvae of C. quinquefasciatus, which were 183 and 408ppm respectively. Raj mohan and Ramasamy (2007) were reported LC50 value of Aegeratina adenophora against A. aegypti and C. quinquefasciatus were 256.70 and 227.20ppm respectively. These concentrations were higher than P. hysterophous, but the authors suggested its use for mosquito control. In the present study the larvae were killed after exposure to sub lethal doses showed bulging of anal papillae as compared to control. This structural distortion of papillae probably led to the death larvae. Similar observations were also noticed in A.aegypti when treated with Aegle marmelos (Samarasekera et al., 2004). Similar dose depantant effect of Lantana camera extracts on third instar larvae of C. quinquefasciatus showed laevicidal activity and cause maximum mortality rate at 3.0mg/ml concentration (Sathish kumar and Maneemegalai, 2008).
In the present study P. hysterophourus leaf extract resulted in high mortality which might be due to the multiple action of a compound or synergestic effects of parthenin. (Narasimhan and Keshava murthy, 1984) and combined effect of other phenolic acids such a caffeic acid, vanillic acid, ansic acid, p-ansic acid, chlorogenic acid and parahydroxy benzoic acid (Oudhia 1998) may possess larvicidal and pupicidal property on A. aegypti and C. quinquefasciatus. Plant extracts have offered many beneficial uses in applications ranging from pharmaceuticals to insecticides. In Homeopathy system, allergies caused by Parthenium can be treated by a drug prepared from Parthenium and in Finland an infusion of Parthenium is used for consumption. In the dictionary of economic plants in India P. hysterophourus is described as a weed found in Poona and is reported to be used as tonic, febrifuge and emmenagogue. Parthenium is also reported as promising remedy against hepatic amoebiasis (Sharma & Bhutani, 1988) and it is used as folk remedy in the Caribbean and Central America (Mabie et al 1996). In Jamaica decoction is used as a flea-repellent both for dogs and other animals (Morton, 1981). Mew et al (1982) demonstrated that sublethal doses of Parthenin exhibited antitumour activity in mice and that the drug could either cure mice completely or increase their survival time after they had been injected with cancer cells. Parthenin, a toxin of Parthenium, is found pharmacologically active against neuralogia and certain types of rheumatism. Pathenin induced dose dependent damage to human leucocyte chromosomes invitro and micronuclei formation in polychromatic erythrocytes of mice is reported (Dominguez & Sierra, 1970). The findings of the present investigation revealed that the leaf extract of P. hysterophous possess remarkable larvicidal and pupicidal property against A. aegypti and C. quinquefasciatus. P. hysterophous is a noxious weed and resource is scanty. The botanical insecticides are generally safer, readily biodegradable non-toxic but active against the insect pest and lack toxicity to higher animals and they do not leave any phytotoxic residues in the environment and active against insect pest. Thus the observation made in the present study have come as yet another evidence for the significant influence of the plant derived botanical pesticide like P. hysterophous in the control of mosquito.
REFERENCE Abbott, W. S. 1925. A method of computing the effectiveness of an insecticide. Journal of Economic Entomology. 18: 265-267. Bounias, M. 2003. Etiological factors and mechanism involved in relationship between pesticide exposure and cancer. Journal of Environmental Biology. 24(1): 1-8. Dominguez, X.A. and A. Sierra. 1970. Isolation of a new diterpene alcohol and parthenin from Parthenium hysterophorus. Planta Medica 18:275-277. Essam Abdel-salam Shaalan, Deon Canyon, Mohamad Wagdy Faried Younes, Hoda Abdel-Wahab and Abdel-Hamid Mansour. 2005. A review of botanical phytochemical with mosquitocidal potential . Environmental International. 31: 1149-1166. Finney, D. J. 1971. Probit analysis. Cambridge University Press, London. Pp. 68-72. Halstead, S. B. 2000.Global perspective on Dengue Research. Dengue Bulletin.24: 77-82. Mew, D., F. Balza, G.H.N. Towers, and I.G. Levy. 1982. Antitumour effects of the sesquiterpene lactone parthenin. Planta Medica .45: 23-27. Morton, J.F. 1981. The puzzling whitetop. Parthenium hysterophorus: Noxious weed, health hazard, folk-remedy, flea repellent. Unpublished report, Univ. of Miami, Florida. Mulla.M.S. 1994. Mosquito control then, new and in the future. Journal of American Mosquito Control Association. 10(4): 574-84. Narasimhan. T.R. and Keshava murthy, B.S. 1984. Characterization of a toxin from Parthenium hysterophorus and its mode of excretion in animals. Journal of Bioscience. 6:729-738. Navie, S.C., R.E. Mcfadyen, F.D. Panetta, and S.W. Adkins. 1996. The Biology of Australian Weeds 27. Parthenium hysterophorus L. Plant Protection Quarterly .11(2): 76-88. Oudhia, P. 1998. Parthenium:A curse for the biodiversity of Chhattisgarh Plains. Abstract. National Research Seminar on Bio-chemical Changes. An Impact on Environment, R.D. Govt. P.G. College, Mandlaa (M.P.) 30-31 July p. 26. Pizzaro, A.P.B, Oliveira-Filho.A.M, Parente.J.P. Melo.M.T.V, Santose.C.M and Lima. P.R. 1999. O aproveitamenoto do residuo da industria do sisal no controle de larvas de mosquitoes. Rev.Soc.Bras.Med.Trop.32, 23-29. Rajmohan, D. and Ramaswamy, M., 2007. Evaluation of larvicidal activity of the leaf extract of a weed plant, Ageratina adenophora, against two important species of Aedes aegypti and Culex quinquefasciatus. African Journal of and Biotechnology 6(5): 631 – 638. Samaraskera.J.K, Khambay. B.P and Hemalal. K.P. 2004. A new insecticidal protolimonoid from Aegle marmelos. Nature product research. 18(2): 117-122. Sathish kumar, M and Maneemegalai, S. 2008. Evalution of larvicidal effect of Lantana camera Linn against mosquito species Aedes aegypti and Culex quinquefasciatus. Advances in biological research. 2(3-4): 39-43. Sharma, G.L. and K.K Bhutani. 1988. Plant based antiamoebic drugs. Part II. Amoebicidal activity of parthenin isolated from Parthenium hysterophorus. Planta Medica. 54:20-22. Vogel, A. I. 1978. In: text book of practical organic chemistry. The English language society and Longman, London. Pp. 1368. REFERENCE Abbott, W. S. 1925. A method of computing the effectiveness of an insecticide. Journal of Economic Entomology. 18: 265-267. Bounias, M. 2003. Etiological factors and mechanism involved in relationship between pesticide exposure and cancer. Journal of Environmental Biology. 24(1): 1-8. Dominguez, X.A. and A. Sierra. 1970. Isolation of a new diterpene alcohol and parthenin from Parthenium hysterophorus. Planta Medica 18:275-277. Essam Abdel-salam Shaalan, Deon Canyon, Mohamad Wagdy Faried Younes, Hoda Abdel-Wahab and Abdel-Hamid Mansour. 2005. A review of botanical phytochemical with mosquitocidal potential . Environmental International. 31: 1149-1166. Finney, D. J. 1971. Probit analysis. Cambridge University Press, London. Pp. 68-72. Halstead, S. B. 2000.Global perspective on Dengue Research. Dengue Bulletin.24: 77-82. Mew, D., F. Balza, G.H.N. Towers, and I.G. Levy. 1982. Antitumour effects of the sesquiterpene lactone parthenin. Planta Medica .45: 23-27. Morton, J.F. 1981. The puzzling whitetop. Parthenium hysterophorus: Noxious weed, health hazard, folk-remedy, flea repellent. Unpublished report, Univ. of Miami, Florida. Mulla.M.S. 1994. Mosquito control then, new and in the future. Journal of American Mosquito Control Association. 10(4): 574-84. Narasimhan. T.R. and Keshava murthy, B.S. 1984. Characterization of a toxin from Parthenium hysterophorus and its mode of excretion in animals. Journal of Bioscience. 6:729-738. Navie, S.C., R.E. Mcfadyen, F.D. Panetta, and S.W. Adkins. 1996. The Biology of Australian Weeds 27. Parthenium hysterophorus L. Plant Protection Quarterly .11(2): 76-88. Oudhia, P. 1998. Parthenium:A curse for the biodiversity of Chhattisgarh Plains. Abstract. National Research Seminar on Bio-chemical Changes. An Impact on Environment, R.D. Govt. P.G. College, Mandlaa (M.P.) 30-31 July p. 26. Pizzaro, A.P.B, Oliveira-Filho.A.M, Parente.J.P. Melo.M.T.V, Santose.C.M and Lima. P.R. 1999. O aproveitamenoto do residuo da industria do sisal no controle de larvas de mosquitoes. Rev.Soc.Bras.Med.Trop.32, 23-29. Rajmohan, D. and Ramaswamy, M., 2007. Evaluation of larvicidal activity of the leaf extract of a weed plant, Ageratina adenophora, against two important species of Aedes aegypti and Culex quinquefasciatus. African Journal of and Biotechnology 6(5): 631 – 638. Samaraskera.J.K, Khambay. B.P and Hemalal. K.P. 2004. A new insecticidal protolimonoid from Aegle marmelos. Nature product research. 18(2): 117-122. Sathish kumar, M and Maneemegalai, S. 2008. Evalution of larvicidal effect of Lantana camera Linn against mosquito species Aedes aegypti and Culex quinquefasciatus. Advances in biological research. 2(3-4): 39-43. Sharma, G.L. and K.K Bhutani. 1988. Plant based antiamoebic drugs. Part II. Amoebicidal activity of parthenin isolated from Parthenium hysterophorus. Planta Medica. 54:20-22. Vogel, A. I. 1978. In: text book of practical organic chemistry. The English language society and Longman, London. Pp. 1368.
About the Author
S.Umavathi and M.Manimegalai
PG & Research department of Zoology, Kongu nadu arts and Science College, Coimbatore-641029, Tamilnadu, India
email:uma_kasc@yahoo.co.in
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