Compact Liquid Crystal Based Fourier Transform Spectrometer System

Abstract

Fourier transform spectroscopy (FTS) is a fundamental analytical tool utilized in many chemical and biological analysis applications. It is especially well-known and widely used for its powerful analytical techniques to measure the spectra of a weakly extended source. The purpose of this study is to create a compact, low-cost FTS system utilizing a miniature liquid crystal interferometer. This design is unique because the optical path difference (or phase difference) is controlled by the applied voltage. The optical path difference is further improved by incorporating two reflective mirrors between the two polarizers. In this article, we will present the theoretical model, numerical simulation, and experimental results of the proposed FTS. Based on the experimental results, the FTS performs in accordance with the theoretical predictions, achieves a maximum optical path difference of 210 m, and a resolution of 1nm at a wavelength of 630 nm. The instrumental response refresh rate is just under 1 second. Absorbance measurements were conducted for single and mixed solutions of deionized water and isopropyl alcohol, successfully demonstrating agreement with a commercial system and literature values.

Electro-hydrodynamic programming reshapes liquid crystal dynamics in free-form director fields

“…Nematic liquid crystals (LCs) have numerous potential applications in the electro-optic field due to their anisotropic optical properties. They have been used as spatial light modulators, compact spectrometers 1 , terahertz filters 2 , and more. Additionally, liquid crystals have many applications in the medical field for optical diagnosis and biosensors 3 .…”

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

“…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.…”