Two-Dimensional Infrared Spectroscopy of Electric-Field-Induced Reorientation Dynamics of a Mixed Nematic Liquid Crystal

A two-dimensional infrared (2D IR) spectrometer has been modified by the following methods to solve several problems on the 2D IR spectroscopy of electric-field-induced reorientation dynamics of a mixed nematic liquid crystal: (1) The response of the liquid crystal (LC) to an electric field was stabilized by an amplitude-modulated ac electric field. (2) Formulation of an anti-reflection coating (ARC) has been proposed to suppress the interference caused by multiple reflections between IR liquid crystal cell windows. (3) The Fourier transform procedure has been modified to correct the phase of the dynamic difference interferograms without spectral anomalies. These modifications can provide a better signal-to-noise ratio and reproducible 2D IR spectrum of a mixed nematic liquid crystal.