Volborthite with 20mW 532nm laser

9:44 AM 10/31/2019

A cheapo 20mW 532nm laser has been installed but not fully tested yet.
It appeared to be a little bit too high in wavelength (~532.7)
while the 532nm Raman LP edge filter (from Tiger Instruments) was 
right at 532.0nm. So I've mounted the laser on a peltier cooled heatsink 
connected to a constant current power source (but without a 
thermocouple to measure the temp). The chilling is expected to 
tune the laser by lowering the wavelength (increasing the frequency) 
so the laser will be maximally and sharply attenuated by the edge filter.

A volborthite sample was burnt by the 20mW laser through 50x objective.
This image shows the black hole left by the laser next to an attenuated 
laser spot shown at the crosshairs.


A volborthite spectrum taken with 532nm @ ~10mW:

The scales are not calibrated and the spectrum is not 
very comparable to RRuFF's.

More work is needed on CCD focus to make sharper peaks.
Sharpness was lost while trying to get the 532nm laser working
through the same beampath as the 633nm.

Both lasers are currently aligned but spectral peak profiles are poor.
The peaks look more like ICBMs instead of the nice sharp peaks that look 
like acid-etched STEM needles. Crococite's main peak at about 838/cm:


CCD focusing and rotation didn't have much of an effect.
Suspecting CCD yaw might be the problem...

Another light leak has been plugged with an extra baffle
in the CCD mount. This has not been tested yet.