This is the sort of technology I envisage Mach using in the future.
Apparently it costs $200 to build such a device.
http://www.youtube.com/watch?v=89sz8ExZndc
You will need to click the start button.

<a href="http://www.youtube.com/v/89sz8ExZndc" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">http://www.youtube.com/v/89sz8ExZndc</a>

Benny,
Very cool!!!!!
Looked all over for more information, but couldn't find any.
So many possibility's with these new advancements.

This is the best I found http://mrl.nyu.edu/~jhan/ftirsense/

I had the advantage of seeing it on a TV show. Thier description of how it works allowed me to modify the attached drawing to show you.

Its one of those, "why did'nt we think of that b4" solutions