3.6 Conclusion

The implications and applications of liquid crystals in spectroscopy and microscopy are quite broad, as is evidenced by the sheer range of topics highlighted in this chapter. Highlighted topics include, foremostly, the investigation of liquid crystal configurations of visible/near-infrared spectrometers and hyperspectral imaging devices. While the liquid crystal Lyot filter is the most mature configuration, other simpler devices using display configurations as tunable photonic crystals are discussed for a variety of applications. A survey of current medical applications of liquid crystal tunable filters as spectrometers in hyperspectral imaging configurations shows the biomedical arena is already benefitting from this technology. The variable retardance capability of a liquid crystal lends these materials to Lyot filters, but also enables the fabrication of microchip Fourier transform spectrometers and polarimeters. Fourier transform spectrometers are a space in which application has been limited to the laboratory bench, as a result of implementation. Select advantages of Fourier transform devices justify studies of alternative instruments; liquid crystal-based configurations are an excellent possibility for voltage driven phase delay elements. Liquid crystal variable retarders may also be used to generate and detect arbitrary polarization states. Coupling these two parameters allows liquid crystals to be implemented in polarimetric and polarimetric imaging configurations to measure specimen properties such as birefringence, depolarization, dichroism, and scattering. The last biomedical application space of liquid crystals, and perhaps the area with the most potential, is alternative uses of liquid crystal spatial light modulators. As liquid crystal spatial light modulators are readily available commercially in...