Wavelength tunable devices based on holographic polymer dispersed liquid crystals

Wavelength tunable devices have generated great interest in basic science, applied physics, and technology and have found applications in Lidar detection, spectral imaging and optical telecommunication. This thesis focuses on the physics, technology and application of several wavelength tunable devices based on liquid crystal technology, especially on Holographic Polymer Dispersed Liquid Crystals (HPDLC).; HPDLCs are formed through the photo-induced polymerization process of photopolymerizable monomers, and self-diffusion process and phase separation process of the mixture of liquid crystals and monomers, when the mixtures of liquid crystals and monomers are exposed to the interfering monochromatic light beams. The information from the interfering pattern is recorded into the holographic liquid crystal/polymer composites, which are switchable or tunable upon external electric fields.; Based on the electrically controllable beam steering capability of transmission HPDLCs, novel switchable circular to point converter (SCPC) devices are demonstrated for selecting and routing the wavelength channels discriminated by a Fabry-Perot interferometer, with application in Lidar detection, spectral imaging and optical telecommunication. SCPC devices working in both visible and near infrared (NIR) wavelength ranges are demonstrated. A random optical switch can be created by integrating a Fabry-Perot interferometer with a stack of SCPC units.; Liquid crystal Fabry-Perot (LCFP) Products have been analyzed, fabricated and characterized for application in both spectral imaging and optical telecommunication. Both single-etalon system and twin-etalon system are fabricated. Finesse of more than 10 in visible wavelength range and finesse in more than 30 in NIR are achieved for the tunable LCFP product.; The materials, fabrication and characterization of lasing emission of dye doped HPDLCs are discussed. Lasing from different modes of HPDLCs is studied and both the switching and tunability of the lasing function is demonstrated. Lasing from two-dimensional HPDLC based Photonic Band Gap (PBG) materials will also be demonstrated. Finally, lasing from polarization modulated grating is discussed.