2009-01-04

All you wanted to know about green laser pointers

About green laser pointers
Green laser pointers have been around for a few years but what are they? We have all seen the red laser pointer but green is completely different. The most common type are DPSSFD, ( diode pumped solid state frequency-doubled). They are much more complicated than standard red laser pointers because laser diodes are not commonly available in this wavelength range and are more expensive to produce. They are also 50 times brighter than red. With green laser's, you can see the beam as well as the very bright dot. Green laser pointers are the preferred laser pointer because green is the most visible laser pointer color. The reason why green is more visible is the human eye is most sensitive to green light. The other reason is the effect of light in the earth's atmosphere. Light is visible in the sky when the atmosphere scatters it and higher wavelengths are scattered more than higher wavelengths. Green is a medium wavelength so it scatters more and is more visible than longer wavelengths such as red. Class 3B lasers may have an output power of up to 500 mW (half a watt) and a laser with an output power of around 100mW and above is easily capable of melting black plastic, making holes in bin liners and popping black coloured balloons or balloons marked with a black marker pen. To give you an idea of what to expect, if you were to enter a room that is pitch black and used the laser on the ceiling, you would be able to see everything in the room. The beam would also be very visible looking like a green rod stretching out. When used outside, the beam seems to reach the stars. The power output of laser's are measured in mW (milliWatts) and can range from 5mW to around 300mW. of course the more power you have, the easier they will burn and the brighter they are.

Infra red filter warning
Laser pointers give out a lot of infrared light which you can't see making them less bright. Laser power meters however cannot distinguish between green light and infrared light. Some inferior laser pointer will normally be made up of mostly infrared light. For example a 100mW inferior laser pointer is likely to have a combination 20mW green (532nm) and 80mW infrared (808nm). All genuine green laser pointers and portable lasers have infrared filters inside them that blocks infrared light. Some laser pointers have had this filter removed or have been manufactured without the filter. Without this filter, these laser pointers are very dangerous because the infrared light can damage your eyes. All the laser pointers we sell contain the correct IR filter.

What to look out for when buying
I have recently noticed cheap fake laser pointers selling at lower than trade prices. i.e. 100mw for about £20 and 200mw at about £40. These are pretty much underpowered lasers like 20mw with a 100mw label attached or 50mw with a 200mw label. If you are buying a laser of about 100mw and above and do not pop black balloons and put holes in black bin liners e.t.c. then it is more than likely that you have purchased a fake.

Important information about a laser lens
The lens on a laser is very sensitive to any dirt or grease particles and when contaminated, it is almost impossible to clean and will require a replacement lens. Most lasers available do not have interchangeable lenses and you will be stuck with a laser that shows a dot surrounded by a blur of dots and lines. The lens on our lasers can be changed in about 30 seconds and we always keep spares for that reason.

Fun things to do with laser pointers
Laser pointers over about 100mW can pop balloons and melt plastic. Dark or black balloons are required because they are better at absorbing green light. White or light coloured balloons will have too much reflection and the absorbed energy will not be enough to pop the balloon. If you don't have any dark/black balloons, you can use a black marker pen to put a black spot on the balloon that you can aim the laser at. These lasers will also burn plastic and put holes through bin liners, of course black objects are better. When pointed on some dark materials, you can literally see smoke rising.

Common laser power output available: 5mw 20mw 50mw 75mw 100mw 125mw 150mw 200mw 300mw

So Many Uses:
Astronomers
Teachers
Students
Bird Watchers
Presentations
Tour Guides
Construction Workers
Scientific
Military
Security applications
Use to point out distant points of interest
Just for fun

How can you be sure the laser you are buying has the correct power output?
Some unscrupulous sellers will offer a high powered laser that is less than half the real power or may not even know the correct power as most sellers do not have access to a proper calibrated power meter. We test each and every laser pointer before it is shipped to you with our state of the art optical power meter from Thorlabs pictured below. The PM121 enables us to accurately measure the precise output power of every laser pointer we supply and guarantee the power before it is shipped! If you are calling to collect the laser, we will demonstrate the equipment for you to see.

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