Please help, powering a laser diode!

[highamperage]

I purchased an IR laser diode recently. There are four pins, 2 for power, and 2 for photo diode? connections. I am wondering what I need to do with these two photo connections? If anything? I am making a simple IR Burning laser, powering it with a battery and a 4.7ohm resistor.

Also, for collimating the beam, I was considering making a lens assembly out of a copper tube and a 6mm lens. However, I have a broken green laser pointer. Do you suppose I could use the lens assembly from that?

I appreciate any help you can provide!


The IR Diode:
http://i8.ebayimg.com/03/i/08/c4/0e/d5_1.JPG

 

[k00zk0]

No no no no nonononononnono!

You need optics and a driver board.

Two of the pins are for power and I'm not sure at all what the third is for, and I'm not sure at all exactly what the driverboard does but I assume it limits current, etc. But there are lots of components inside it. A single resistor might provide the same thing as the entire driverboard but it won't be as good. Again let someone else answer that. I just wanted to tell you fast before you kill it or your eyes.

You need optics in front of the diode as it shoots out IR like an LED, just from a very fine point. Think a green laser pointer without the converting crystals. I'm sure they dont do much in the refraction of light internally, so remove them and youll get a perfect beam of IR, unless the lenses work differently with infrared at 808nm. In that case fix the focus with an IR sensative material infront of the lense till its a beam, and wear googles always

EDIT: sorry I kindof read your post quickly but you did realise you need lenses for collimination. Didn't catch that. Yes you can use a lense assembly from antoehr laser but as I said I think the lenses work differently at a different lambda, so youll need goggles and some sortof IR sensative material. Actually thinking abotu that again, paper or wood itself will work fine as when it ignites or burns you know you got a tight beam.

 

[jkaiser3000]

The diode has three pins that I can see, and that's the common thing to have. One pin is tied directly to the case, and is usually the negative terminal. One of the other two pins is the laser diode positive terminal, and the third pin is the photodiode, in case that diode has one (not all do).

Using a battery and the resistor is ok for short periods, but is a risky way to power that thing. You'd be better off using a dedicated diode driver, or build one yourself. It should have, preferably, automatic power control (APC), but can be tricky to implement that approach if the diode doesn't have a photodiode. In that case use an automatic current control (ACC).

Also, you can use a laser pointer's case, although you may need to readjust the focus to get a well collimated beam

P.S.: oh, yeah, I forgot, wear eye protection