Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Why and when do laser diodes shift in wavelegth?

MrMcChicken

MrMcChicken

0
Joined
Mar 6, 2011
Messages
279
Points
28
Hello everyone, there is a question I have and I hope somebody here can help me out.
Does the wavelength of a laser diode depend on the current it is driven or on the temperature it heats up during high currents? If it would depend mostly on a high current it would be pretty neat, because I would really like to have a 470nm laser but DPSS are quite expensive. So I could just pulse it with high power pulses to get the shift in wavelength but don't have to struggle with extreme high power CW output. (well, for me everything higher than 100mW is already high power).

Greetings, MrMcChicken :yh:
 





Cyparagon

Cyparagon

0
Joined
Sep 12, 2007
Messages
9,399
Points
113
Higher current translates to a higher wavelength. Higher temperature also translates to a higher wavelength. To what extent depends on the diode. A cold violet on low current for example could be 403nm. The same violet might be upwards of 420nm when warm and with high current. With blues, violets, and greens, the current will have a greater effect on wavelength.
 
CurtisOliver

CurtisOliver

0
LPF Site Supporter
Joined
Jun 12, 2015
Messages
7,610
Points
113
Also pushing this to the extreme. Check out this video from a member here. I don't recommend actually doing this if you happen to have some liquid nitrogen lying around, but it does prove the point on temperature. :)https://www.youtube.com/watch?v=5PquJdIK_z8
 
Last edited:
  • Like
Reactions: GSS
BobMc

BobMc

0
Joined
Apr 23, 2016
Messages
3,685
Points
113
That was a really cool video, thanks for sharing. Very informative.
 
Rivem

Rivem

0
Joined
Feb 16, 2016
Messages
1,214
Points
83
Just to add, there are two major mechanisms that influence the wavelength shift in laser diodes:
  • Semiconductor bandgap changes- Energy difference that electrons experience across the semiconductor becomes different.
  • Lasing Medium/Cavity Changes- The geometry of the laser itself can change with temperature and shift wavelength.

Of course the average operating temperature and load current are very closely related.
 
MrMcChicken

MrMcChicken

0
Joined
Mar 6, 2011
Messages
279
Points
28
Thanks for sharing this video. This looks pretty amazing. However it doesn't seem to be a very practical method. Sadly most diodes don't shift that much. Has anybody did some tests of different diodes? I have seen some threads where single diodes were tested and got some information on DTRs site.

Greetings, MrMcChicken
 
  • Like
Reactions: GSS
CurtisOliver

CurtisOliver

0
LPF Site Supporter
Joined
Jun 12, 2015
Messages
7,610
Points
113
MrMcChicken said:
Thanks for sharing this video. This looks pretty amazing. However it doesn't seem to be a very practical method. Sadly most diodes don't shift that much. Has anybody did some tests of different diodes? I have seen some threads where single diodes were tested and got some information on DTRs site.

Greetings, MrMcChicken
Click to expand...
Lol, I wasn't proposing it to be a practical method. Just showing you the extremes. :D
Your right most diodes under normal operating conditions will only shift a few nm either way. I contacted Styropyro before on this matter, and the 650/635's tend to shift more and don't thermal damage as easily as the 520's. I don't know about the 445/450/465's etc. But I take it that they will behave similar to the 520's as it seems that InGaN doesn't like thermal tweaking as much AlGaInP.
 
CurtisOliver

CurtisOliver

0
LPF Site Supporter
Joined
Jun 12, 2015
Messages
7,610
Points
113
Lol. Out of these lasers, which one would you choose?
You could have a wonderful liquid nitrogen cooled 580nm diode that you would have to handle with gloves.
Or a 589 that you can use normally.
9nm makes a difference you know. :D
 
G

GSS

0
Joined
Apr 28, 2015
Messages
5,069
Points
113
MrMcChicken said:
Thanks for sharing this video. This looks pretty amazing. However it doesn't seem to be a very practical method. Sadly most diodes don't shift that much. Has anybody did some tests of different diodes? I have seen some threads where single diodes were tested and got some information on DTRs site.

Greetings, MrMcChicken
Click to expand...
Pman, pushed a few "costly":eek: 07 diodes hard just to see and got some good results kinda recently. None seemed to fry out.
I'm not to sure on what thread he posted it?
 
Last edited:
Radim

Radim

0
Joined
Aug 17, 2016
Messages
1,458
Points
83
CurtisOliver said:
Lol. Out of these lasers, which one would you choose?
You could have a wonderful liquid nitrogen cooled 580nm diode that you would have to handle with gloves.
Or a 589 that you can use normally.
9nm makes a difference you know. :D
Click to expand...

I pesonally love complexity - I would go for DPSS laser, where the process of creation of output radiation is just amazing. :)
 
You must log in or register to reply here.




Top