[Laser] Focus\Power Question

[J. Forster]

kd7jyk@ross-technologies.com wrote:

> I read of an LED laser putting out roughly 16 watts, but it was pulsed at
> 0.001s.

First, a LED is not a laser. A LED (Light Emitting Diode) is an incoherent
emitter. A laser is an entirely different animal.

> How do they get the higher power output, do they increase the voltage or
> current for the pulse?

Both. Laser drive pulses are 5 to 15 volts at several (sometimes many) amps.

> I have a 16.5W IR LED array, but not coherent light.  How would I increase the
> W when pulsed?

If you look at the LED specs, they will give allowable drive currents and times
(pulse width and rep rate). Go from there. In general the shorter the pulse, the
higher allowable current. It's basically an internal power dissipation limit.
For example, some outdoor LED displays are pulsed to increase the perceived
brightness. By pulsing, you can increase the PEAK power, but likely not the
AVERAGE power.

> Can the non coherent IR be focused to burn a small hole in tissue or typing
> paper?

Maybe. I've not tried it. If you use several LEDS, it will not be trivial to get
all the outputs into one place so the powers sum up.-John

> Kurt