PEPSIOS Purely Interferometric High-Resolution Scanning Spectrometer III Calculation of Interferometer Characteristics by a Method of Optical Transients*

Abstract

A method is described by which series expressions may be obtained for the transmittances of spectrometers in which light paths are independent of frequency. Since the spectrum (the square of the Fourier transform) of a light pulse is a continuum of uniform height in the limit of zero pulse duration, the square of the Fourier transform of the pulse train transmitted by a spectrometer illuminated by such a pulse is proportional to the transmittance of the system. The total energy transmitted by an instrument illuminated by an arbitrary spectrum may be expressed as a sum of terms each containing the Fourier transform of the spectrum; thus any such instrument is in a sense a Fourier spectrometer. The method has been used to investigate basic characteristics of the Fabry–Perot and Michelson interferometers, the effects of flatness imperfections in Fabry–Perot interferometers, and to develop expressions for the energy transmitted by PEPSIOS spectrometers.