ALTERNATIVE BEAM SPLITTER/COMPENSATOR CONFIGURATIONS FOR REDUCTION OF MULTIPLE REFLECTIONS IN IMAGING FOURIER TRANSFORM SPECTROMETERS

Eight alternative beam splitter/compensator con-figurations for use in imaging infrared Fourier trans-form spectrometers are presented The objective is to identify one or more configurations that may reduce multiple reflection problems in imaging Fourier transform spectrometers. The alternative configura-tions include: (1) dual slab with antireflection coat-ings, (2) dual slab at angles other than 45 ~ (3) dual slab with no air gap, (4) dual slab with widened air gap, (5) square 45 o cube, (6) hexagonal 60 ° cube, (7) vertically stacked parallel slab, and (8) vertically stacked non-parallel slab. A description and brief analysis of each alternative configuration is included The conclusion is that the dual slab with widened air gap configuration exhibits the best potential for reduc-ing multiple reflections in imaging Fourier transform spectrometers. I. Background The techniques of Fourier Transform Spectroscopy using the Michelson interferometer have been in de-velopment since the 1950s.1 The fundamentals of these techniques were well documented in the 1970 Aspen International Conference on Fourier Spectros-copy.