Laser Damage to Liquid Crystal Alignment Materials in Ordinary and Extraordinary Modes

We report on the laser-damage threshold of common liquid crystal alignment materials, including rubbed polyimides, rubbed nylon, and a photoaligned azobenzene. The photoaligned azobenzene is, in principle, more laser-damage resistant because of the no-touch processing in the clear aperture¹ with the added benefit of ease of scaling and processing. We further compare the polarization dependence of the damage threshold with respect to the alignment direction in ordinary and extraordinary modes at a near-infrared wavelength. Studies on polarization dependence on laser damage of liquid crystals with alignment layers have been very limited,² and none include photoalignment. Laser-damage thresholds depend substantially on the presence of aligned liquid crystal materials. We also compare laser-damage–threshold dependence on the electrical actuation state of the nematic liquid crystal material. These data inform design of high-power beam-shaping devices for applications in fusion, 3-D printing, and defense systems.<br/><br/>This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856, the University of Rochester, and the New York State Energy Research and Development Authority.<br/><br/>1. K. L. Marshall<i> et al.</i>, Proc. SPIE <b>8828</b>, 88280N (2013).<br/>2. K. L. Marshall, K. R. P. Kafka, N. D. Urban, J. U. Wallace, and S. G. Demos, “Multiparameter Laser Performance Characterization of Liquid Crystals for Polarization Control Devices in the Nanosecond Regime,” accepted at Nature: Scientific Reports.