Nonlinear absorption and refraction of linearly polarized nanosecond laser radiation by liquid crystals in the transient regime: 532-nm, 2-10-Hz mode

Summary form only given. It is very important to create photonic devices (e.g., optical power limiters, switches) for green, Nd:YAG pulsed laser radiation. Previously, it was shown that 25-100-/spl mu/m path-length liquid-crystal (LC) layers may have, for nanosecond, 532-nm irradiation, extraordinarily high values of nonlinear absorption coefficient /spl beta/, and refractive coefficient n/sub 2/ even in the transient regime, which is of considerable practical interest. Two competing mechanisms drive the value of n/sub 2/ in LC media in the nanosecond regime: (1) the orientational nonlinearity (with relaxation time of the order of tens to hundreds of nanoseconds) and (2) thermal and density ones. Which of the mechanisms dominates, depends on the preparation of the LC layer, laser pulse duration, /spl beta/, and the incident-beam spot size. For this reason the work aims at understanding how preparation of LC layers influence this nonlinear response.