Proposal for High-Resolution, Wide-Bandwidth, High-Optical-Throughput Spectroscopic System Using a Fabry—Perot Interferometer

Abstract

We propose a high-resolution, wide-bandwidth, high-optical-throughput spectroscopic system, in which a Fabry–Perot interferometer (FPI) is used in tandem with a second spectrometer. As the second spectrometer, one of the following three instruments can be used: (1) a grating dispersion-type monochromator attached to a multichannel detector (MCD), (2) a conventional Fourier transform spectrometer (FTS), or (3) a multichannel FTS (MFTS). The principle of operation for the three systems is the same. First, we adjust the free spectral range ( FSR) of the FPI to be k (>1) times the data interval DI (or resolved wavenumber) of the second spectrometer. The FSR is divided by N (> k) equally, and the etalon plate spacing of the FPI is changed N times with a step interval of FSR/N in wavenumber. Thereby we gather a total of N spectra from the second spectrometer. Finally, a single high-resolution spectrum is synthesized from the N spectra. To demonstrate the real capabilities of the proposed systems, we present computer simulation results.