Q: What is calculation of final output from the IR

[benkokes]

Hello,

I bought a diode from eBay and it gives an output of 350-400mw IR laser "P" in the 808nm spectrum. I was wondering how to calculate the final green output.
How do I figure out how efficient the doubler crystal is?

If there any link to final output power and input current at a known voltage (3v and 390mA max)? or are all diodes too different to make an assessment just based on input current?

Thanks,
-Ben

 

[DaFiend]

you won't be able to find that out until you have converted the IR to 532. Every crystal is different.
If the output of IR is 400mW, and you get 40mW, the efficency will be 10%, with that particular crystal. If you get 80mW effiecency is 20%.

 

[Raccoon]

It should be noted that the effiecency of a green dpss laser is extremely low. Typically 5~8%?

And the standard reminder, not to be critical, but safety first. "Never power a high powered IR diode without eye protection." Your 350-400mW diode will make your retna pop. Vision will be gone from that point on.

 

[benkokes]

When you say that the efficiency is low, you are talking about input power to output optical power in IR, correct?
I see the power transfer in 3 stages. T
1)The power into the diode,
2)the IR beam out of the diode,
3)then that inputting into the crystal and then the "doubled" frequency out of the crystal.
SO there are 2 points of energy loss, one at the electrical/IR conversion, and one at the 808/532 conversion.
I assume that the 808/532 conversion is pretty inefficient (about 10% max), hence why a 50 mW IR beam only outputs 3-4mW in the green spectrum.
So then the question of the day is where can I get a higher transmissive frequency doubling crystal that will not break the bank?

 

[Raccoon]

From a higher power laser module, I think. This is like the engine/transmission of a car. It would be cheaper to simply buy one already assembled for the output you want.

If you want a BMW, don't buy an Escort.

 

[benkokes]

I understand that. I am just curious how to do the calculations. I assume I am correct that the final output is dictated by the transmissive efficiency of the crystal.