Green light lasers

[sumerw]

A few years ago this was all the rage, and everyone was talking about how a green laser would show up much clearer than a red laser in daylight.

Haven't heard anything in a while. Does anyone know what happened to the idea?

[Stopdropnroll]

Grant that this is kind of an oversimplified explanation...

Green light is much more visible than red light...when you look at light transmission it look like a bell curve...red being half way up on the right..blue being half way up on the left...Green being at the peak of the bell. (desirable) So a green laser is the "Holy Grail" of light transmitters....

Red lasers are 633nm...(visible to the human eye)
"Green" lasers are 1060nm, (twice the wavelength) they start out in the Infer-red spectrum, (not visible) So...to make the green laser visible they take a "doubler" chip and place it in the laser diode. This breaks the output of the laser to half and places the now "green" laser in the visible spectrum...

So why are laser companies not using them?....

Life-Diode life is currently about 150 hours for a "green" laser compared to 20,000 to 40,000 hours of red laser diodes.

Battery life/power draw-where red laser has about 4 hours constant on with (2) watch batteries or 30 hours constant on time with just 123 lithium flashlight battery... With a green laser using watch type batteries you would get about a 5 second "constant on" time...I don’t know the on time for a CR 123 lithium flashlight batterybut I do know that currently a battery of that size would be the only option...(your laser just got REAL BIG)

Heat/Bulk-The "doubler chip" is very resistant as it must dissipate 1/2 of the power that comes to it...so lots of heat is generated, therefore the laser diode would be very bulky to allow enough room for the heat to dissipate. Remember that much bigger battery we needed power up and give reasonable "constant on" time to this diode earlier?...because we are using a much bigger battery we getting much more heat in our confined space of our diode.

Cost... currently a (raw) red laser diode is about $7 when bought in bulk... a (raw)green diode is about $175....

So with current technology... for about a $700-$1000 a company could build you a reasonably sized, fragile, laser that would last for 5 seconds or a very bulky hot laser that would last about 100 to 150 hours...neither option very appealing.

Hope this helps... SDnR ;)