Multichannel Fourier-transform infrared spectrometer

Abstract

A compact Fourier-transform IR spectrometer without a moving mechanism was developed. The spectrometer consists of a shearing interferometer for forming a spatially distributed interferogram and an IR array detector for observing the interferogram. The shearing interferometer of the developed system is a birefringent interferometer with a Savert plate; the IR array detector is a PtSi Schottky- barrier detector with 4096 elements. The optics and the system configuration are described in detail, and the experimental results of the IR absorption spectra of polystyrene and polyethylene terephthalate film are shown. The developed optics is as small as 20 × 6 cm ϕ in size. The spectral resolution of the prototype system is ~ 27.6 cm⁻¹ between 5000 and 2000 cm⁻¹. The methods and their possibilities of resolution improvement are also described.