Spectrum of the Baader-U colored shiny faces

[Hornblende]

Hi all,

I have a little hand spectroscope for identifying gemstones, I thought it would be interesting to take a look at the spectrum of the Baader-U colored reflections.

Photo taken with an Iphone.

 

Red side:

 

Yellow/green side:

[OlDoinyo]

Interesting. The green gap in front might be justified by the fact that the UG11 glass is an efficient absorber of those wavelengths, so the dichroic coating need not be too efficient there. I am surprised by the gaps in the blue and red ends--but what do I know? Perhaps it is enough that they do not line up front-to-back.

[colinbm]

If you put one on top of the other I think that is all the Vis + IR all reflected, just leaving the UV to pass ?

[Cadmium]

Hornblende, Can you diagram your set up for that test?

Thanks.

[Hornblende]

Cadmium, of course. Here it is.

 

[Cadmium]

Wow! Thanks! That is an excellent diagram! Very helpful.

Then you attach the spectroscope to your camera somehow?

[Hornblende]

It is a hand spectroscope, so I try to take a photo with my iphone of the eyepiece of the spectroscope.

[OlDoinyo]

The diagram depicts an illumination angle far inclined from the normal axis. Dichroic coatings do not perform as designed under these circumstances. Perhaps the reality of the setup was more favorable.

[Hornblende]

I tried at a more right angle, the lines shift a little and become sharper.

I couldn't take a good quality picture.