498nm line from 575nm lasence module

[Sowee7]

Some time ago, I bought a yellow 575nm lasence module. When I received it, I turned it on immediately, when I tested it on my spectrometer, I saw it had two lines, one at 577nm and one at 580nm. I decided to try putting different pieces of dichroic glass over it to see if I can get any ir lines or maybe some other visible not lasing emission. When I put a piece of glass that let's blue through but reflects yellow, and then put a diffraction grating over that, I saw a blue and a yellow line. By putting another piece of the same glass over the first piece of glass, almost all of the yellow was gone and I was left with a blue-cyan spot which I measured with my spectrometer to be 498nm. I have no Idea what it is from and if it is even laser emission. I'll post some pictures bellow

 

[Sowee7]

https://imgur.com/a/hzzSVi9

 

[liveforphysics]

That is amazing. I could try similar tests with the Lasence 571nm module and see if they behave similarly.