Application principle of spatial light modulator

A spatial light modulator refers to a device that can modulate a certain parameter of the light field through liquid crystal molecules under active control, such as modulating the amplitude of the light field, modulating the phase through refractive index modulation, modulating the polarization state through rotation of the polarization plane, or achieving incoherent coherent light conversion, thereby writing certain information into the light wave and achieving the purpose of light wave modulation. It can easily load information into one-dimensional or two-dimensional light fields, utilizing the advantages of wide bandwidth and multi-channel parallel processing of light to quickly process the loaded information. It is the core component that constitutes real-time optical information processing, optical interconnection, optical computing and other systems.

Generally speaking, spatial light modulators contain many independent units arranged in a one-dimensional or two-dimensional array in space. Each unit can independently receive optical or electrical signals for control and change its optical properties according to these signals, thereby modulating the light waves illuminated on it. This type of device can change the amplitude or intensity, phase, polarization state, and wavelength of spatial light distribution under the control of time-varying electric driving signals or other signals, or convert incoherent light into coherent light. Due to its properties, it can be used as a construction unit or key device in real-time optical information processing, optical computing, and optical neural networks systems.

Space light modulators can generally be divided into reflective and transmissive types based on the different readout methods of the readout light; According to the different input control signals, it can be divided into optical addressing (OA-SLM) and electrical addressing (EA-SLM).