Operating temperatures of Diodes and DPSS

While going through the forum threads, its become clear that green DPSS modules do not function well at low temperatures.
What about diodes(MT140 etc.,)
Is there some kind of chart of temperature vs output.

That said, at -20 degree C, your duty cycle should increase since the diode will have a hard time getting hot if there is a nice heatsink in your host. Battery life for Li-Ion would be very low though.

Operating temperature (at datasheet) varies from diode to diode, and from crystal to crystal.

Nichia specifications for the NDB7875 is 0~50ºc operation.

At -20ºC, you should be worried about the condensation forming everywhere. AND from what I've seen, cooling a diode makes the wavelength lower. For reds, it makes the wavelength deviates to orange, for blues, it makes wavelength deviate to violet.

This deviation STILL depends on output power, for example, one lpc-826 @ threshold current, outputs 657nm, @ 600mA its λ = 666nm.

Edit: Diodes efficiency (mW/mA) depends on temperature too.
Thanks shokkunlasers for pointing it!

The ML520G54 has eficiency:

0.71mW / mA @ Tc = 15ºc (140mA needed for 100mW)
0.47mW / mA @ Tc = 60°c (210mA needed for 100mW)

IMO temperature has a great effect to the output power (as far as you dont have condensation on the diode or lens) It depends on the specific diode how strong its power changes with the temperature
The new 638nm diodes for example are highly influenced by temperature
See in
the datasheet for the single mode 638nm page 3 :beer:
http://www.orthotoronto.com/pdf/ML520G54.pdf

Leodahsan said:

Operating temperature (at datasheet) varies from diode to diode, and from crystal to crystal.

Nichia specifications for the NDB7875 is 0~50ºc operation.

At -20ºC, you should be worried about the condensation forming everywhere. AND from what I've seen, cooling a diode makes the wavelength lower. For reds, it makes the wavelength deviates to orange, for blues, it makes wavelength deviate to violet.

This deviation STILL depends on output power, for example, one lpc-826 @ threshold current, outputs 657nm, @ 600mA its λ = 666nm.

There is no chart (I've seen) for temperature / output. It depends on how you cool the diode!

Click to expand...

but would that damage the diode tho?
If it wouldn't .
I think I'll start chilling my 635nm diodes in liquid nitrogen to make them orange :shhh:

@piggy
Re-read post. Don't forget that diodes have an operating temperature.

@all
Damn I forgot it. Really temperature have a big impact at efficiency, hence affecting output power. Ill correct my original post to make things clearer thanks.

EpicHam said:

but would that damage the diode tho?
If it wouldn't .
I think I'll start chilling my 635nm diodes in liquid nitrogen to make them orange :shhh:

Click to expand...

There one who already did this:shhh: But hes very professionial and his setup is really good

here you go :beer:
https://www.youtube.com/watch?v=z8EuZwgdqQ4&feature=c4-overview&list=UUR8_o56gONuwwJnZ3rfosmg

_edit oh picked the wrong vid here is the right one i meant https://www.youtube.com/watch?v=0w4czym1FFg

shokkunlasers said:

There one who already did this:shhh: But hes very professionial and his setup is really good

here you go :beer:
https://www.youtube.com/watch?v=z8EuZwgdqQ4&feature=c4-overview&list=UUR8_o56gONuwwJnZ3rfosmg

_edit oh picked the wrong vid here is the right one i meant https://www.youtube.com/watch?v=0w4czym1FFg

Click to expand...

oh damn!
Thats look so FUN!!!!

With such setup , a 30% efficient 608nm output will finally be possible