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.

液晶为光学应用和光操纵提供了独特的多功能平台。实际上，除了众所周知的液晶显示器实现之外，基于液晶的技术，尤其是空间光调制器（SLM），还可以实现对各种波长和光功率下光束的相位和振幅的有效控制。由于它们在宽范围的电磁光谱中具有透明性，光学选择性和高双折射性，因此液晶可以在宽范围的光波长和波长范围内实现光学功能，例如光谱滤波器，光整形，延迟线和移相器。输入功率取决于所考虑的特定配置和材料。在这篇评论中，我们概述了我们在液晶光阀方面的成就，光学寻址的SLM，它将液晶与光敏材料结合在一起，以优化整个介质的电光响应。我们展示了光阀表现为非线性光学介质的能力，其中可以通过各种交互方案进行光波混合。重点介绍了不同的应用，例如慢光，干涉测量，光学传感和动态全息。