Multiple Time Scales Optical Nonlinearities of Liquid Crystals for Optical-Terahertz-Microwave Applications

We provide a critical account of the dynamics of laser induced refractive index changing mechanisms in nematic liquid crystals which may be useful for all-optical switching and modulation applications in the visible as well as the Terahertz and long-wavelength regime. In particular, the magnitude and response times of optical Kerr effects associated with director axis reorientation, thermal and order parameter changes, coupled flow-reorientation effects and individual molecular electronic responses are thoroughly investigated and documented, along with exemplary experimental demonstrations. Emphases are placed on identifying parameter sets that will enable all-optical switching with much faster response times compared to their conventional electro-optics counterparts.