Compact liquid-crystal-polymer Fourier-transform spectrometer

Abstract

We present the optical design and realization of a low-resolution liquid-crystal (LC) Fourier-transform spectrometer (FTS). This FTS is based on a polarization interferometer that has a Wollaston prism made of a LC material as a key component. It has a compact design, a good acceptance angle, and low temperature dependence and can be fabricated with cost-effective LC technology. Because the LC is polymerized, it is robust, and the temperature dependence is drastically reduced. The performance of a compact handheld version of the spectrometer and the characteristics (angular dependence, resolution, stray light, and temperature dependence) will be discussed.

Method of realizing compact Fourier transform spectrometer without moving parts based on birefringent liquid crystal

“…(8), and the result is given in Fig. 3(b), which shows that the spectrum of the laser light is correctly determined with the full width half maximum (FWHM) of 10.5 nm.…”

“…A liquid crystal (LC) is a good birefringent material because of its large tunable refractive index, low driven voltage, and fast response, all of which have been widely researched in birefringent FTS. [8][9][10][11][12][13][14][15] The primary methods of LC birefringent FTS are based on a Wollaston prism with spatial interference 8-10 and a binary voltage-controlled LC stages with time interference. [11][12][13][14][15] For the spatial interference, the fringes are recorded by a detector array, which may increase the error due to the noise difference of the subdetectors.…”

Accurate color predictability based on a spectral retardance model of a twisted-nematic liquid-crystal display

“…This is the case of Fourier transform spectroscopy [17,18], where LC devices offer a new design and unattended monitoring implementations instead of using moving parts components. Also for the pulse shaping of femtosecond lasers [19,20], where different phases are encoded onto different spectral components by means of the LCD.…”

Microscopic birefringence imaging by phase-shift interferometry using a liquid crystal phase shifter

“…[7] If we extend the shifting range of the phase shifter, it can apply to a Fourier transform spectrometer without any mechanical moving parts. [8][9][10] Since the phase change is considerably limited even though we use very thick LC cells, available spectrum range is only higher frequency regions. However, it is enough to use as a spectrometer for visible rays and/or near infrared region.…”