Spectral analysis of light intensity fluctuations caused by orientational fluctuations in nematics

Publisher Website
Google Scholar
Abstract
In this paper we discuss the homodyne and heterodyne experimental technique for the detection of noise intensity spectra of laser light scattered by nematic liquid crystals (n.1.c.). We have studied the influence of laser noise on both homodyne (section 2) and heterodyne (section 3) experiments. It turns out that the laser intensity fluctuations are of importance only in the heterodyne case. It is shown experimentally that the linewidths of homodyne spectra are twice those of heterodyne spectra, which indicates that the statistical process of the director fluctuations is Gaussian (section 5). The influence on the measurements of stray light and the number of coherence areas subtended by the photodetector is discussed briefly in sections 4 and 5. Neither disturbing factor affects the linewidths of the light intensity spectra. In section 6 we discuss and summarize the principal results obtained