Little current,high power?

Hi, i think to buy this 808nm,500mw laser diode from ebay.But I can not believe that laser diode of 500mW pull current of 350mA @ 2.2V.
Is this appropriate for the current diode or is fake.
I ask this because I use red laser diode that consume 500mA of current @ 3.2V for 300mW of power.

p.s.I have see another 9mm 808nm laser diodes with same power(500mw) but they consume 650mA.

In theory its possible. A photon of 808 nm has 1.5 electronvolts of energy, so for a current of 1 mA you could get 1.5 mW output if quantum efficiency* were 100%.

Practically it never is though, for a decent quality 808 nm diode i would calculate with about 1 mA of current for 1 mW output. 808 nm diodes are more efficient then reds in general, but the differences is not that enormous.

* i.e. number of electrons passing through that cause emission of a photon. There is also loss in the supply voltage being higher then the photon energy which is something different.

Where do you see 350mA? I see "Working Current: I<580mA"

Before I post here question I ask seller it is that true current for this diode.And he today correct value to 580mA(max 650).

I have buy green laser pointer (10mW) and will extract old diode and insert my new 500mW diode.But can crystal handle 500mW of power?
Which is efficiency of crystal?How much can I expect the final output power?

That sounds really hard and stupid, how are you going to take out the old diode? believe me, its hard. And I'm not sure, but I think you need a special type of 808nm diode, not 100%. But swapping out the diodes is pretty impossible, and if you mess up the crystals, you will have a really hard time to align it properly again.

If your pointer is of the type where the vanadate crystal is glued to the KTP, then the only things you'll have to worry about are:

1. Not damaging the crystal set by touching them, or moving their position the slightest bit.

2. Doing #1 while removing the old laser diode

3. Keeping track of the orientation of the chip on the old diode relative to the crystal set. This is so you can place the new one in, at the same orientation "angle" as the old one.

You can mark the back of the old diode with a fine marker tip, with a line which say is drawn from a diode pin, all the way till you're marking the brass diode sleeve, in which the diode is mounted.

Remove the diode, and take note of how the line you marked is oriented relative to the chip that lies behind the diode's window.

Now, relative to the chip on your new diode, make a similar mark in the same place where the mark on the old diode landed.

When installing the new diode, line up the marks you made on the new diode, to those on the brass mount.

Its really not quite so tedious, but the above just spells it all out so you get the idea: Make sure the diode is properly rotated to the proper angle, and make sure the diode is installed as deep/flush as possible.

Post pictures as you do the repair! :beer:

If is so hard as you say I can lathe new host/heatsink for diode,crystal and lens.This laser pointer have only one crystal(glued on brass half ring).And one focusing lens.Crystal has light green color on his both ends.Dimensions of crystal are 1x1x3x milimeter.
But I worry about crystal that they cant handle 500mW of power.

There are parts of laser pointer.From left to right: Laser diode,crystal/lens,body,focusing lens.

EXO said:

Before I post here question I ask seller it is that true current for this diode.And he today correct value to 580mA(max 650).

Click to expand...

That seems more typical for a 500 mW pump diode indeed. The typical current for these pumps when used in green laser modules is 600 to 650 mA, some draw 700. This could mean they are operating the pump at over 500 mW to get more output, no way to tell without taking the thing apart though.