Self-starting phase conjugation with liquid crystals

Summary form only given. Liquid crystals are technologically important electro-optical materials, as they possess many unique physical and electro-optical properties. They have also been shown to be technologically important nonlinear optical materials. Extraordinarily large optical nonlinearities are exhibited over the entire visible-near infrared-infrared spectrum; nonlinear optical responses to CW, microsecond, nanosecond and picosecond lasers have been documented. Among the various physical mechanisms, perhaps the most noteworthy ones are those associated with temperature and director axis (orientational) fluctuations. As a result of molecular correlation effects, and the critical behavior of the order parameter near the phase transition temperatures T nematic liquid crystals exhibit the by now well known property of large thermal index gradients Another property of the nematic phase is the large susceptibility of the crystal axis to weak external field, i.e., orientational fluctuations can be easily induced. In this presentation, the author describes how these thermal and orientational fluctuations may be fruitfully utilized in some noise initiated self-starting coherent nonlinear optical devices