Liquid crystal THz optics – An overview and recent advances
Recently, the science and technology of sub-millimeter or terahertz (THz) waves have made progress by leaps and bounds. Applications in fields ranging from bio-medicine, 3D imaging, tomography, and characterization of materials have been demonstrated. Sub-THz radio-over- fiber communication at data rate exceeding 20 Gb/s over a 25 km fiber link was also demonstrated. To meet the demands of the exploding THz field, many novel quasi-optic components, such as phase shifter, phase grating, polarizers, and filters have been developed. In particular, a number of tunable THz devices employing liquid crystals (LCs) have attracted considerable attention. Partly, the unexpected large birefringence of liquid crystals and low attenuation in the THz frequency range is responsible for the realization of such advances.
In this talk, we provide an overview of the field liquid crystal THz optics and discuss recent advances in the field. After a brief introduction to THz technology, the optical properties of liquid crystals in the THz frequency range will be presented. This is followed by an overview of various THz optical components with liquid-crystal-enabled functionalities, e.g., phase shifters, polarizers, birefringent filters of Lyot and Solc types, phase grating and beam deflectors, and so on.