will a diode cooled with liquid nitrogen wor

[charleytown55il]

 what would it do wavelength-wise if it did work? would the diode even work? i would try it if i had liquid nitrogenn :'( :'( :'(

 

[iewed]

Re: will a diode cooled with  liquid nitrogen

I doubt it.

 

[VillageIdiot]

Re: will a diode cooled with  liquid nitrogen

huh? if you had the right system and didn't freeze your diode (lolz) then sure it'd work. I dunno what you mean by wavelength-wise... why would it change wavelengths? imo it'd be more trouble than it's worth...

 

[styropyro]

Re: will a diode cooled with  liquid nitrogen

why would it change wavelengths?

The wavelength of the light emitted from a laser diode usually varies slightly with the temperature.

 

[VillageIdiot]

Re: will a diode cooled with  liquid nitrogen

Yeah, but he's just keeping it at optimum by making sure it doesn't overheat, right?

 

[Spyderz20x6]

Re: will a diode cooled with  liquid nitrogen wor

Ive heard what works is just pouring liquid nitrogen all over your diode... ;D
You could try cooling it with water like they do with computers. You could buy N[sup]2[/sup]O online, it is not a controlled substance. The tanks cost a lot though, the nitrogen is about as expensive as milk, but the tanks can be around $80. You need the tank to store the nitrogen in.

 

[likewhat]

Re: will a diode cooled with  liquid nitrogen

The gain curve is related to temperature so it would change the wavelength. I got a 808 to go to 803 by cooling it from room temp to 0 C. Of course all diodes are different but usually the wavelength goes down with temperature. Lots of people cool diodes to cryogenic temperatures, I dont know if they are going for wavelength change or efficiency or what though. If you are just trying to change the wavelength you can build something called an external cavity diode laser. With one of these I was able to get that same 808 nm diode down to 778 nm at room temp, it just depends on what you want to do.

 

[Things]

Re: will a diode cooled with  liquid nitrogen

You can dump your diode in liquid nitrogen and overpower it alot, condenstion will build up inside the diode and ruin it. A countless number of times have i thought about "covering" my diode in ice from my TEC, but its hard to keep moisture out, which will wreck ur diode.

 

[Spyderz20x6]

Re: will a diode cooled with  liquid nitrogen wor

That would be cool if they had mini TEC's, that you could fit inside a small project box.

 

[Spyderz20x6]

Re: will a diode cooled with  liquid nitrogen wor

Are there peltier plates that can run off a 9 volt battery?

 

[daguin]

Re: will a diode cooled with  liquid nitrogen

That would be cool if they had mini TEC's, that you could fit inside a small project box.

http://www.ferrotec.com/products/thermal/modules/miniModules.php

 

[chido]

Re: will a diode cooled with  liquid nitrogen

That would be cool if they had mini TEC's, that you could fit inside a small project box.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1197272621

 

[Spyderz20x6]

Re: will a diode cooled with  liquid nitrogen wor

Thanks guys!!! That REALLY helped, as i am starting a new project

 

[flogged]

Re: will a diode cooled with  liquid nitrogen

Most red and IR LD's tend lase at higher frequencies the lower the temp. For example there's a cooled 635nm diode can sometime be pushed < 630nm.

However, there are limits.. from SAM's laser FAQ (http://privatewww.essex.ac.uk/~bolat/laserfaq.html#diobcc6):

The wavelength shift for 808 nm diodes is generally around 2.5 nm (+/- 0.2 or 0.3 nm) per 10 °C, with the wavelength shift to the red with increasing temperature.

(From: Lynn Strickland (stricks760@earthlink.net).)

It really depends on the laser (i.e., manufacturer) and temperature range you are talking about. A good rule of thumb is 0.3 nm per °C over the operating temperature range of the device (About 30 GHz per °C). That's the average slope of the curve though - it includes mode hops. If you're operating at a mode hop, you can get a lot more change than 30 GHz with a 1 °C temperature change. If you are between mode hops, it can be much less.

Mode hops can be a moving target too. Optical feedback can cause them (even minute amounts). Or, you can operate at a specific temperature where there are no mode hops today, but next week it might mode hop at that temperature.

Note that you can only go so far if you want to use temperature to reduce the wavelength. Even if you got the electronics to work under frigid conditions, there is a minimum laser wavelength you can get from a particular diode laser chip. I'm not a physicist, but it has to do with the bandgap of the materials used. What you would get, as you cooled the thing, is lower and lower threshold current, lower operating current, and longer lifetime.

So there is a wavelength shift with temperature.

However, there's another practical concern if you're planning on cooling the diode to liquid nitrogen temperatures: the glues used in its construction will likely delaminate

 

[Spyderz20x6]

Re: will a diode cooled with  liquid nitrogen wor

Do you think it would be effecient to run both the LD and the peltier plate using one 9 volt battery? I was thinking to do it like this:

Oops, i forgot to draw the 300mA driver that is between the switch and the peltier plate...
Just pretend there is a 300mA driver connecting from the switch to the peltier plate.

 

[flogged]

Re: will a diode cooled with  liquid nitrogen

No, a nine-volt battery will not be able to supply the current needed to do this... at least not for more than about 10 seconds.