Diode temperature

[bulldog_99_00]

Hi everyone,

I bought a cheap red laser diode (emission at 200mW but dropping to 150mW as it heats up) as well as a peltier junction. I want to experiment with TEC cooling.

But I was wondering: I know lasers have warm-up times, so the crystals have to be at a certain temperature to efficiently lase. What is that temperature? 25°C? 50°C?

Thanks

Simon

[buffo]

You're confusing DPSS laser operation with that of a direct injection diode. Your red is a direct injection diode - it doesn't have any crystals. You simply want to keep it cool.

DPSS designs, on the other hand, often have a pair of peltier coolers. One is used to cool the diode, while the other is used to warm the frequency-doubling crystal. And yes, in this case the temperature control of the crystal (KTP, LBO, KNB03, or BiBO) is crucial. (The temperature of the lasing crystal, either YAG or Vanadate, is not nearly as important.)

Bottom line, hook up your TEC and cool the didode as much as you can. Don't get too crazy though - you don't want to have to deal with condensation issues! But the colder the better in your case.

Adam

[mixedgas]

You're confusing DPSS laser operation with that of a direct injection diode. Your red is a direct injection diode - it doesn't have any crystals. You simply want to keep it cool.

DPSS designs, on the other hand, often have a pair of peltier coolers. One is used to cool the diode, while the other is used to warm the frequency-doubling crystal. And yes, in this case the temperature control of the crystal (KTP, LBO, KNB03, or BiBO) is crucial. (The temperature of the lasing crystal, either YAG or Vanadate, is not nearly as important.)

Bottom line, hook up your TEC and cool the didode as much as you can. Don't get too crazy though - you don't want to have to deal with condensation issues! But the colder the better in your case.

Adam

Dont fully drive the peltier on, use it a bit below its rated voltage and current, or it becomes a bit of a heat source on you. There is a curve to its response. pelteir cooler controllers are cheap.

Steve

[bulldog_99_00]

Thanks for the info guys. The more you know

Steve, I did a quick google search for peltier controllers and came up empty-handed. Could you recommend a particular company/supplier?

I found a circuit diagram, so I could build one myself. It usually ends up being more expensive than just buying it, though.

[allthatwhichis]

Here is a lot of 10 that has already been sold...

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=011

I think the guy has more.

[dave]

Thanks for the info guys. The more you know

Steve, I did a quick google search for peltier controllers and came up empty-handed. Could you recommend a particular company/supplier?

I found a circuit diagram, so I could build one myself. It usually ends up being more expensive than just buying it, though.

Speak to Robin - uk-laser around these parts