Applied Nanophotonics, Liquid Crystals and Biomedical Optics

The most common configuration of liquid crystal devices incorporated within spectral imaging systems is using liquid crystal tunable filters. Usually, these filters suffer from low light throughput or slow response times which may not meet the growing demands of industry and research. However, in most applications, multispectral imaging is adequate, and there is no need for hyperspectral imaging. We implemented a discrete tunable Lyot-based filter in such systems to obtain spectral images more efficiently. The Lyot filter consists of three liquid crystal cells combined with nine narrow bands of passive filter covering the visible-infrared spectroscopy and near-infrared spectroscopy, which makes it a potential candidate for various applications. A system with a smaller number of bands designed for oximetry imaging is even faster and shows higher light throughput. Experimental results show that our approach yields a relatively faster response with high light throughput while providing reliable spectral information for food quality assessment and remote sensing applications.