Optical Spectroscopy in the Mineral Spectroscopy Lab. (Prof. G.R. Rossman)

Optical Spectroscopy.  We are now using diode array technology that allows rapid capture of spectra. It was built by visiting Research Associate, Michael Taran, around a Nicolet-SpectraTech NicPlan infrared microscope.
 

The diode-array microspectrometer.
 The spectographs.  One is for the Near-Infrared (900 -1650 nm) and the other is for the Visible-UV region (230 - 1050 nm).

The area to measure is defined by projecting the image of an apeture on the sample.  Typical sample areas are 100 x 100 micrometers or smaller.
Light sources for the spectrometer system:  Deuterium, Xeon Arc, and Tungsten lamps

Diode Array Dectectors.  512 channel InGaAs on top, 1025 element Si on the bottom (and at left).

Earlier Instruments

Original Diode-Array System


Our orginal diode-array system as initially configured with a vertical optical bench for samples under a black cloth.  To the left is our original petrographic microscope that could be coupled to the system through fiber optics.
 		  
The sample location in the optical bench spectrometer.  The rotation stage allowed the sample to be rotated in different orientations above a Glan-Thompson calcite polarizer.

Cary 17I


This recording spectrometer obtained data on chart paper that was subsequently hand-digitized.