Is there a need in a driver?

[theshutgun]

If i have a regular LED all I need to do is connect to it a resistor and a power source... And if i have a laser diode, which is just like a light emitting diode, why do I need a full circuit for a driver?
My laser diode works on 2.2V and 1.2A and uses 1.5Watt of power... do i really need a driver with LM317 and a capacitor?

 

[Blord]

http://laserpointerforums.com/f51/i-want-build-laser-thread-52972.html

Read the driver section.

 

[Meatball]

Materials - wise, LEDs and LDs are indeed very similar, but their structure differences leave LDs more susceptible to electrically induced damage - ESD, spikes etc.

 

[Things]

The #1 cause of laser diodes failing is from catastrophic optical damage, whereby increased power levels damage reflective coatings on the laser cavity, meaning it no longer (or very faintly) lases. LED's can't fail this way, thus they are much more tolerant.

You CAN power a laser diode from a resistor IF you can be 100% sure the voltage will remain constant, so that the power into the laser diode is always the same. Alternatively you can run the laser diode well below it's specifications and it'd survive on a resistor - but most people here push them to the limits, so you need active regulation.

 

[theshutgun]

Thanks!!!
Another question, On optics if a laser light of one long wave length passes through a lens or a material other then void or air it shortens its wave length...
If my laser is 808nm and i run it through a 450nm lens, the wave length will be 625nm, right?

 

[Meatball]

The delta lambda is more of an effect of the refraction index of the optic piece - how quickly does a material absorb and re-emit an incident photon? The change is usually on the order of fractions of a nanometer - or nanometers difference for very slow materials. The difference also Only appears while the wavefront is Inside the optic. Once the beam reaches the transition to air, it will again become its original wavelength/original speed.

 

[lasersbee]

Thanks!!!
Another question, On optics if a laser light of one long wave length passes through a lens or a material other then void or air it shortens its wave length...
If my laser is 808nm and i run it through a 450nm lens, the wave length will be 625nm, right?

I would suggest that you do a little reading and research
on the forum or even Google about Lasers.
Try searching Coherent Laser light..

To answer your question.............. NO!!!

BTW... you are in the wrong section of the Forum.
This is were this Thread should have been posted....

Blu-Ray & Violet Lasers - Laser Pointers


Jerry

 

[theshutgun]

You are right! I have forgot that it changes the wave in the optic...
Thanks anyway!!!

 

[Cyparagon]

If my laser is 808nm and i run it through a 450nm lens, the wave length will be 625nm, right?

The wavelength changes back as soon as it exits the material again. Color (energy) of a photon is technically based on frequency anyway, and frequency does not change with a change in the medium.