surefire L72 or what is the new green laser
- Thread starter oldeng95
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carbonsparky
Enlightened
$57 is cheap for a green laser. Where did you see this?
If you are asking why they cost more than red diode lasers, it is because the green laser pointers are much more complex.
Red diode lasers are made up of a laser diode (red or maybe orange emitting) a driver circuit and collimating lens.
Green laser pointers use infrared laser diodes to pump a Nd:YAG crystal. This energy being injected into the crystal causes it to lase or produce laser light in the green spectrum, this is than ran through a collimator to clean up the beam shape. The green laser pointer needs to be carefully tuned to work. From what I understand, you just can't slap the crystal in expect things to work. It has to be placed just right.
Check out these links for a better idea of what I tried to explain. http://www.thinkgeek.com/gadgets/lights/5a47/images/
http://www.repairfaq.org/sam/laserpic/glpdpics.htm
If you are asking why they cost more than red diode lasers, it is because the green laser pointers are much more complex.
Red diode lasers are made up of a laser diode (red or maybe orange emitting) a driver circuit and collimating lens.
Green laser pointers use infrared laser diodes to pump a Nd:YAG crystal. This energy being injected into the crystal causes it to lase or produce laser light in the green spectrum, this is than ran through a collimator to clean up the beam shape. The green laser pointer needs to be carefully tuned to work. From what I understand, you just can't slap the crystal in expect things to work. It has to be placed just right.
Check out these links for a better idea of what I tried to explain. http://www.thinkgeek.com/gadgets/lights/5a47/images/
http://www.repairfaq.org/sam/laserpic/glpdpics.htm
The_LED_Museum
*Retired*
Here's my "simplified" explanation of how a green laser pointer works:
In a 532nm green laser (pointer or larger size), there's a BIG infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element "neodymium". This crystal takes the 808nm infrared light and lases at 1064nm (yes, deeper in the infrared!). This 1064nm laser light comes out of the NdYV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that doubles the frequency to 532nm - the bright green color you see. This light is then collimated (focused) by a lens and emerges out the laser's "business end". Just before the lens, there's a filter that removes any stray IR (infrared) rays from the pump diode and the neodymium crystal. You don't want that stuff in your green beam, trust me. /ubbthreads/images/graemlins/smile.gif
In a 532nm green laser (pointer or larger size), there's a BIG infrared laser diode that generates laser light at 808nm, this is fired into a crystal containing the rare-earth element "neodymium". This crystal takes the 808nm infrared light and lases at 1064nm (yes, deeper in the infrared!). This 1064nm laser light comes out of the NdYV04 (neodymium yttrium vanadium oxide) crystal and is then shot into a second crystal (containing potassium, titanium, & phosphorus, usually called KTP) that doubles the frequency to 532nm - the bright green color you see. This light is then collimated (focused) by a lens and emerges out the laser's "business end". Just before the lens, there's a filter that removes any stray IR (infrared) rays from the pump diode and the neodymium crystal. You don't want that stuff in your green beam, trust me. /ubbthreads/images/graemlins/smile.gif
Size15's
Flashaholic
The SureFire Green Laser Aiming Module is not a retail part.
Certainly not for $57. Not even for $570 I bet.
Al
Certainly not for $57. Not even for $570 I bet.
Al
IsaacHayes
Flashlight Enthusiast
I thought lasers even red used a crystal to bounce the light around until it all came out in one direction.. Is this true or do they just use optics? If so those are some small effeiceint optics. Wonder what a luxeon with those would do...
BTW what causes the grainy, "moving static" look in red lasers?
BTW what causes the grainy, "moving static" look in red lasers?
kakster
Flashlight Enthusiast
Why a green laser for aiming? You can see the whole beam of a green laser (not just the dot). Surely this would make it easier for the bad guy to spot your location?
The_LED_Museum
*Retired*
The bad guy would be able to see the beam from a red laser too, even if you really couldn't; the green has more of a "cool factor" to it, which is probably why they're being offered. I wouldn't be surprised to see blue and violet directly-injected laser sights being offered when the price comes down.
carbonsparky
Enlightened
[ QUOTE ]
IsaacHayes said:
I thought lasers even red used a crystal to bounce the light around until it all came out in one direction.. Is this true or do they just use optics? If so those are some small effeiceint optics. Wonder what a luxeon with those would do...
BTW what causes the grainy, "moving static" look in red lasers?
[/ QUOTE ]
Red laser diodes have a specially made semiconductor junction that functions like the YAG crystal in the green laser. The diode itself is the laser crystal. It emits a kind cone shaped beam which is pulled together into a round beam by the collimator lens.
IsaacHayes said:
I thought lasers even red used a crystal to bounce the light around until it all came out in one direction.. Is this true or do they just use optics? If so those are some small effeiceint optics. Wonder what a luxeon with those would do...
BTW what causes the grainy, "moving static" look in red lasers?
[/ QUOTE ]
Red laser diodes have a specially made semiconductor junction that functions like the YAG crystal in the green laser. The diode itself is the laser crystal. It emits a kind cone shaped beam which is pulled together into a round beam by the collimator lens.
mattheww50
Flashlight Enthusiast
The moving static so to speak is a result of constructing and destructive inteference. Unless the laser is an exact mutliple of a wave length, light (photons) is emitted from the laser all at the same wavelenght, but with different phase angles, which result in the Moire like patterns as the in phase photo strength, and out of phase weaken at various points in the beam.
In general gas lasers emit very tight beams. This is because the gain per pass through the laser tube is very small, so it takes many passes back and forth to get appreciable gain. One result is that the beam inside the tube has to be very tightly aligned, so the beam escaping out the pin hole is equall well aligned!
In theory a solid state laser would not have to be carefully aligned.
In general gas lasers emit very tight beams. This is because the gain per pass through the laser tube is very small, so it takes many passes back and forth to get appreciable gain. One result is that the beam inside the tube has to be very tightly aligned, so the beam escaping out the pin hole is equall well aligned!
In theory a solid state laser would not have to be carefully aligned.
