Blacksberg
J
Jet
Propoulsion Laboratory, California Institute of Technology,
Pasadena, CA 91109, USA
Maruyama
Y, Charbon E
Delft University of Technology, Delft, The Netherlands
George R. Rossman
Division
of Geological and Planetary Sciences, California Institute of
Technology,
Pasadena,
California 91125, USA
ABSTRACT
We
incorporate newly-developed solid-state detector technology into time
resolved
laser Raman spectroscopy, demonstrating the ability to distinguish
spectra from
Raman and fluorescence processes.
As a
proof-of-concept we show fluorescence rejection on highly fluorescent
mineral
samples willemite and spodumene using a 128x128 single photon avalanche
diode (SPAD) array with
a measured photon detection efficiency of 5%. The sensitivity achieved
in this
new instrument architecture is comparable to the sensitivity of a
technically
more complicated system using a traditional photocathode-based imager.
By
increasing the SPAD active area and improving coupling efficiency we
expect
further improvements in sensitivity by over an order of magnitude. We
discuss
the relevance of these results to in situ
planetary instruments, where size, weight, power, and radiation
hardness are of
prime concern. The potential large scale manufacturability of silicon
SPAD
arrays make them prime candidates for future portable and in situ Raman instruments spanning
numerous applications where
fluorescence interference is problematic.