strange 505nm emission coming from lasence 575nm modules

[Sowee7]

hello,

recently i got my 5th 575nm module, ive notice something strange about all of them though, all of them have a strange greenish-turquoise color that is emitted along with the 575nm light, if you lower the current bellow the 575nm lasing threshold, the turquoise light is still there, ive heard from many other people that it was also emitted in the old OPTlaser 575nm lasers. even though both my OPTlaser 565nm lasers and my OPTlaser 560nm lasers didint emit any of the green light. ive also heard from another member that the emission is 20nm long so it isnt laser emission, ive also noticed that the updated modules (made july-present) dont have that much 505nm light if any. also the light is very weak. could it be some anti-stokes process?

 

[paul1598419]

I have one of the Opt Lasers 575nm lasers and have looked at it with my Ocean Optics spectrometer. It has a clean line at 574nm and no other lines that I saw. IDK what you are looking at.

 

[Sowee7]

I have one of the Opt Lasers 575nm lasers and have looked at it with my Ocean Optics spectrometer. It has a clean line at 574nm and no other lines that I saw. IDK what you are looking at.

it is very weak emmision, look in with your phone camera when its bellow lasing threshold also put an ir filter to block out most/all of the ir

 

[paul1598419]

Yeah, it uses an IR pump diode, so I doubt any other lines would appear below laser threshold. My spectrometer's lower limit runs out around 850nm. Its upper limit is around 350nm. I have many cameras and could look at it with any of them as I have done in the past. The 574nm line looks green on all of my cameras but is clearly yellow.

 

[Sowee7]

Yeah, it uses an IR pump diode, so I doubt any other lines would appear below laser threshold. My spectrometer's lower limit runs out around 850nm. Its upper limit is around 350nm. I have many cameras and could look at it with any of them as I have done in the past. The 574nm line looks green on all of my cameras but is clearly yellow.

mine does, the green light is vissable when you shine it at a white surface (ir filtered) also its not
laser emission

 

[ZRaffleticket]

Paul, typically this is visible pre-threshold. Is yours in a position where you can turn down the current? Best I can show is this:

 

[Sowee7]

Paul, typically this is visible pre-threshold. Is yours in a position where you can turn down the current? Best I can show is this:
View attachment 73270

yea but WTF is that, is it some sort of anti stokes effect, or could it be something frequency doubled inside the crystal, its defenitly not the pump thats doubling as the pump is 940nm and 940 doubled is 470nm

 

[Sowee7]

UPDATE: by adding another oc, i managed to actually get ≈500nm laser emission from the laser

 

[paul1598419]

Paul, typically this is visible pre-threshold. Is yours in a position where you can turn down the current? Best I can show is this:
View attachment 73270

You know, I haven't tried to drop the current down that far. I really don't see a reason to try. At 20 mW and above the line is 574nm and nothing else. Where did you get this spectrum from?

 

[Sowee7]

You know, I haven't tried to drop the current down that far. I really don't see a reason to try. At 20 mW and above the line is 574nm and nothing else. Where did you get this spectrum from?

you dont need to drop the current, i think the 505nm line is an actual lasing line, though it is very weak, see my previous post

 

[paul1598419]

you dont need to drop the current, i think the 505nm line is an actual lasing line, though it is very weak, see my previous post

If you are using a camera to decide if there is green in this spectrum you will be disappointed as the cameras, CCD and CMOS, all look green. You need at least a diffraction grating if not a spectrometer to see if you have any other lines. I looked at all of your posts and don't see any spectrums.

 

[ZRaffleticket]

You know, I haven't tried to drop the current down that far. I really don't see a reason to try. At 20 mW and above the line is 574nm and nothing else. Where did you get this spectrum from?

I took it myself, opt 572nm module and just turned down the current.

 

[paul1598419]

I took it myself, opt 572nm module and just turned down the current.

Which spectrometer do you have? I wasn't aware that you had one. Is it one of the Ocean Optics? If it is one of the B&W Tec spectrometers I'm not sure if that works as well. I've had trouble getting those to work as well as the OO ones.

 

[Sowee7]

If you are using a camera to decide if there is green in this spectrum you will be disappointed as the cameras, CCD and CMOS, all look green. You need at least a diffraction grating if not a spectrometer to see if you have any other lines. I looked at all

i can litterally see the greenish blue dot.... and even on camera you can see a difference between the 2 dots

 

[ZRaffleticket]

Which spectrometer do you have? I wasn't aware that you had one. Is it one of the Ocean Optics? If it is one of the B&W Tec spectrometers I'm not sure if that works as well. I've had trouble getting those to work as well as the OO ones.

Yeah I bought it earlier this year, Ocean optics usb2000. Range is 380nm-1050nm. Calibration is pretty good against my known dpss and gas wavelengths

 

[paul1598419]

Yeah I bought it earlier this year, Ocean optics usb2000. Range is 380nm-1050nm. Calibration is pretty good against my known dpss and gas wavelengths

That's great! I know you've been wanting one.....so good for you. You can recalibrate it yourself if you want to.