The influence of polarization direction on the visibility of the new Fourier transform spectrometer based on Wollaston prisms

Abstract

Fourier transform spectroscopy has evolved over several decades into an analytic spectroscopic method which application throughout the physical, chemical, and biological sciences. The conventional Fourier transform spectrometer (FTS) is based on a scanning Michelson interferometer. To overcome the limitations induced by mechanical scanning device in the Michelson interferometer, there are several types of FTS with non-scanning system were presented. One of them utilizes the polarization element such as Wollaston prism or Savart plate. In this paper the principle of a new FTS based on a Wollaston prism array is presented. Compared with the conventional polarization FTS, it has higher spectral resolution and optical throughput. There are many factors have influence on the fringe visibility of FTS. Here we focus on discussing the influence of the fringe visibility affected by the direction of the polarization elements in this FTS. The fringe visibility of the interferogram is the function which variables are the small angles departure of the theory polarization direction α, β. When the value of the fringe visibility is given, the values of angle α, β, are obtained. This is helpful to the alignment of the polarizing elements during the construction of polarization interferometer. The spectrum which uses the He-Ne laser as the optical source is acquired and recovered through the Fourier-transform program. At present time the spectral resolution of this system is 4 nm.