Liquid crystal light valves as optically addressed liquid crystal spatial light modulators: optical wave mixing and sensing applications

Liquid crystals offer an unique versatile platform for optical applications and light manipulation. Indeed, besides the well-known realization of liquid crystal displays, liquid crystal-based technologies and, particularly, spatial light modulators (SLM)allow achieving efficient control of the phase and amplitude of optical beams at various wavelengths and optical powers. Thanks to their transparency in a wide range of the electromagnetic spectrum, optical selectivity and high birefringence, liquid crystals offer the possibility of implementing optical functions, as spectral filters, light shaping, delay lines and phase shifter, in a wide range of optical wavelengths and input powers depending on the particular configuration and materials considered. In this review, we present an overview of our achievements on liquid crystal light valves, optically addressed SLM that combine liquid crystals with a photosensitive material in order to optimize the electro-optical response of the medium as a whole. We show the ability of light valves in behaving as nonlinear optical media where optical wave mixing can be performed with various interaction schemes. Different applications, such as slow light, interferometry, optical sensing and dynamic holography, are highlighted.