Trouble telling the difference between IRs and Reds

I've read in some other forums that its possible to find out a infra red diode from a red laser diode (from a dvd burner) by checking it with a multimeter.
Could someone explain how to use the multimeter and what the multimeter will say if its an infrared diode or an red laser diode?:undecided:

some extra information if needed (i got a fluke multimeter and i disassembled my samsung ts-h542 dvd burner to find two lasers. Both display similar colouring of the laser when attatched to a battery.)

First of all don't attach a diode directly to a battery. The "KipKay" method is the best way to turn your laser diode into an expensive LED.

I haven't heard of using a DMM to test for an IR diode but I've found the easiest way is the IR will almost always have a small plastic lens on the end it while in its heat sink. The red will not. I can't say this will always hold true but it has in the three pioneer's I've torn apart. (two were 16x drives and one 4x) One was even nicely marked with a red stripe on the red's heatsink and a blue on the IR.

I still test the one I think is the red by attaching it to a 42ma DDL driver. This is usually enough to make the diode lase but not enough to overheat it. If you have the red you'll know it. The IR one will give off a dim cherry red colored light. What ever you do DO NOT look directly at the diode. It is also giving off a ton of invisible to you IR that can damage your eye!

Thanks for that
I'm pretty sure that i found out which diode is which now. Now im having problems with focusing the laser
Thanks anyways :wave: