richnormand wrote ...

@HighVoltageChick

May I suggest reading this before exploring further,

In particular the note about IR leakage from DPSS lasers (what you have here) later in the article they comment on how to separate the IR from the visible. Considering that in some cases the IR could account to close to half the output power it is generous to call that leakage!

Another link you should explore is;


and



Happy reading and keep safe. These small units can roll or topple and the beam can hit your eye. It takes only a fraction of a second to result in a retinal burn or worse. To give you an idea at that power level (100mW) in my lab we have a door interlock and all personnel have laser google.

richnormand wrote ...

Took some pics, hope that helps.

Setup is composed of a green laser module designed for a pen enclosure similar to the one you have. I embedded it in an Al heatsink to run it CW. Camera was an Olympus E500 with its IR filter present. I used a FGW Find-R-Scope IR to visible converter to image the IR light. Power was about 20 mW, as read with a Newport 1815C calorimeter power meter (reads heat from all wavelengths simultaneously) The diffraction grating was a cheap plastic 1" square from Edmonds used in school demos.


First photo is the setup with the laser on the right, grating in the middle taped to a 2 by 4 wood block and a screen made from a 8 by 11 notepad.. You can see the FGW on the table beside it. My glasses are next to it because I am wearing laser goggles while doing this.

Second is the screen with the visible first and second 532nm green spots and markings on the location of the 800nm pump IR and 1060nm fundamental IR beam as located with the FGW.

Next (#3) is an IR image with the FGW. Note the light spot and mess of scattered light at 800 nm right in the middle. This looks green because the FGW green phospor (as in the night vision googles). Compare with the second photo or the last photo in the dark in the visible only: there is nothing there. In the IR you see lots of light all over the place. The foremost left and right spots are the visible green light and the mess and extra spot in the middle is the laser light you do not see. But wait there is more!

The 1060nm light is focussed and right next to the second order diffrated green light on the right. It is hard to see on the camera, almost where the green is and just as bright but located about 1mm to the outside as indicated on the screen in the second photo. I would need a closeup lens for that or post a trace from the spectrometer. But I think the point is made. The nice green spot you see mask a lot of other IR ligth that has to be well filtered in a good laser. By omitting these filters one get an inflated reading from the power meeter from the IR light "leaking".

richnormand wrote ...

klugesmith wrote ...

Fantastic photos and explanation there, Rich.
Is the disreputable laser module in "as purchased" condition?

Did you then accidentally bump your own post, adding no new content?
Original has the time label 13:58, quoted entirely in reply at 14:01 (PDT).