What Is A Spatial Light Modulator?

Spatial light modulator means that under active control, it can modulate some parameters of light field through liquid crystal molecules, such as modulating the amplitude of light field, modulating the phase through the refractive index, modulating the polarization state through the rotation of the polarization plane, or realizing the incoherent – coherent light conversion, so as to write certain information into the light wave, to achieve the purpose of light wave modulation. It can easily load information into one or two dimensional optical field, and make use of the advantages of wide band of light, multi-channel parallel processing and so on to process the loaded information quickly. It is the core component of real-time optical information processing, optical interconnection, optical computing and other systems.

Operating principle of spatial light modulator

Generally speaking, a spatial light modulator contains a number of independent units, which are arranged in a one-dimensional or two-dimensional array in space. Each unit can receive the control of optical signal or electrical signal independently, and change its own optical properties according to the signal, so as to modulate the light wave illuminated on it. Such devices can change the amplitude or intensity, phase, polarization state and wavelength of optical distribution in space, or convert incoherent light into coherent light under the control of electrically driven or other signals that change with time. Because of this property, it can be used as the construction unit or key device in real-time optical information processing, optical computation and optical neural network systems.

The spatial light modulator can be divided into reflection type and transmission type according to the different reading mode of light. According to the input control signal, it can be divided into optical addressing (OA-SLM) and electrical addressing (EA-SLM).

Application of spatial light modulator

Liquid crystal light valve using light – light direct conversion, high efficiency, low energy consumption, fast speed, good quality. It can be widely used in optical computing, pattern recognition, information processing, display and other fields, and has broad application prospects.

Spatial light modulator is a key device in modern optical fields such as real-time optical information processing, adaptive optics and optical computation. To a large extent, the performance of spatial light modulators determines the practical value and development prospects of these fields.

Main applications, imaging & projection, beam splitting, laser beam shaping, coherent wavefront modulation, phase modulation, optical tweezers, holographic projection, laser pulse shaping, etc.