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ArcticMyst Security by Avery

In how cold temperature does a 445nm still work?

TuhOz

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Aug 23, 2011
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Hello,

I've been wondering this as I got my 445nm ready.

Strangely I couldn't find answer to this question.

So can I use a diode 445nm laser in -5C....-15C?
Can low temperature damage the diode/driver?

Winters are cold in Finland... so I want to know how much I can use it outside :p

Btw my laser is M140 diode w/ Flexdrive @ 1.2A

Thanks!
 





Joined
Sep 12, 2007
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The diode and circuitry will be fine, but battery performance will suffer a lot.
 
Joined
Dec 11, 2011
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It was -15C here last night in northern Michigan, no problems with my 50mW 445nm pointer... other than my fingers not wanting/able to hold down the pushbutton well. I wish pointers had tail clickies.

Batteries do not like the cold though, they will die if kept under their minimum temps.
 
Joined
Nov 11, 2009
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The clicky on my Cree sometimes gets "funny" in really cold weather.
 

jimdt7

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Feb 5, 2011
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Yeah, DPPS lasers are very sensitive to wheather conditions !

Jim
 
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Mar 27, 2008
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478
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Actually, laser diodes and laser crystals LOVE the cold. Diodes run best when they're submerged in liquid nitrogen, in fact. Same with DPSS crystals.

The problem is that cold diodes shift their wavelength output. What used to be an 808nm diode at room temperature is now probably closer to an 812nm diode in the freezing cold. The diode shifts right out of the absorption band of the DPSS crystal and your DPSS output drops to nothing.

Driver circuits like being cold as well, though perhaps not liquid nitrogen cold. They should be fine even in freezing cold weather.

What won't be fine is your batteries, and some types of mechanical buttons and switches. So for the sake of those, keep your laser warm! :)
 
Joined
Jun 27, 2011
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No, the laser as a whole (DPSS) hates the cold. As the individual electronic components get colder they become more efficient, which may change how they work with the other parts, ex. the wavelength of the 808nm diode changing.
 
Joined
Mar 27, 2008
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Precisely. I've driven a Nd:YVO4 + KTP crystal combo at -78 degrees C and it worked better than it did at room temperature.
 




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