31 October 1997 Development and testing of a MWIR Fabry-Perot interferometer for hyperspectral imaging
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This paper describes the theory of design, operation, and testing of a tunable MWIR Fabry-Perot interferometer operating in low orders. This device is called the agile bandpass tunable filter (ABTF) due to the fact that the spectral bandwidth can be changed by a large factor by changing the order. In first order the system can be tuned over the entire 3.5-5 micrometers spectral region with only a single order sorting filter. We provide a short introduction to tunable filters an then briefly discuss the requirements that low order operation places on the Fabry-Perot dielectric mirrors. Operation in low orders forces one to abandon the classical Fabry-Perot approximation that the mirrors are negligibly thin compared to the plate separation. Rather, one must now account for the phase properties of the dielectric stack mirrors as they produce phase effects comparable to the plate separation. We next address the issue of control of the Fabry-Perot. This is accomplished through a closed-loop system using capacitive sensor on the Fabry-Perot flats to measure the separation of the plates. Additionally we describe how the ABTF is characterized using a FTIR to measure the bandpass shape and position, and we show some examples of measurements made with the ABTF used as a hyperspectral imaging system with a 256 X 256 HgCdTe camera. We conclude with a discussion of potential applications and future work.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert Ryan, Robert Ryan, Richard G. Madonna, Richard G. Madonna, Theodore W. Hilgeman, Theodore W. Hilgeman, John D. Hulsmann, John D. Hulsmann, William C. Van Nostrand, William C. Van Nostrand, Lawrence Lesyna, Lawrence Lesyna, Nils J. Fonneland, Nils J. Fonneland, J. Michael, J. Michael, Lewis L. Smith, Lewis L. Smith, S. Mielke, S. Mielke, } "Development and testing of a MWIR Fabry-Perot interferometer for hyperspectral imaging", Proc. SPIE 3118, Imaging Spectrometry III, (31 October 1997); doi: 10.1117/12.278938; https://doi.org/10.1117/12.278938

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