A spatial light modulator (SLM) is a device that can control the intensity, phase, or polarization of light beams in a spatially varying manner. SLMs are commonly used in applications such as projectors, optical communication, and holography. They work by manipulating light at the pixel level, allowing for complex patterns and images to be formed. There are different types of SLMs, including liquid crystal and microelectromechanical systems (MEMS). Liquid crystal SLMs use liquid crystal molecules to modulate light, while MEMS SLMs use tiny mirrors to reflect light. Both types enable precise control over light, making them valuable in scientific and industrial applications.