How Spatial Light Modulators Speed Optical Computing Applications

A spatial light modulator (SLM) applies spatial varying modulation on a light beam. An SLM when placed on an overhead projector for displaying computer monitor content to a screen. It explains why modern projectors are developed with an inbuilt SLM for different presentation requirements. It is important to understand how spatial light modulators speed optical computing applications. Read on to understand more.

An SLM modulates light beam intensity. However, devices can be produced modulating the beam phase and intensity simultaneously. SLMs are applied extensively for storage of holographic data setups. The SLMs are useful in encoding information into a laser beam with the preciseness and transparency of an overhead projector. Additionally, SLMs are applied in holographic display technology in holographic optical tweezers. Liquid crystal SLMs solve laser micro-particle manipulation problems after dynamically changing the spiral beam parameters. 

SLMs in optical computing

There is a growing trend of SLMs in diffractive optics for making lenses in a correlator. The SLMs have refractive lenses for their optics. For refractive optics, the curved lenses are handcrafted and aligned to each other. The lenses in diffractive optics are like bumps on glass sheets mounted closely and easily aligned. Diffractive lenses are designed like integrated circuits making it possible to make them in bulk cheaply. Monolithic design of SLMs allows correlators to be integrated with one or two integrated circuits. 

Electrically addressed SLM 

This type of SLM creates an electronically changed image. The EASLM receives input through a regular interface like VGA or DVI input in resolutions of about QXGA (2048 × 1536). Electronically addressed spatial light modulators have a small active area measuring about 2 cm² and are not meant for direct viewing like regular displays. When choosing an EASLM, an Lcos Spatial Light Modulator from a reliable microscope equipment supplier is a wonderful idea. 

Optically addressed SLM

Also known as a light valve, this type of SLM creates and changes an image by encoding a shining light on its front or back surface. By use of a photo-sensor, the OASLM senses the pixel brightness for replicating the image using liquid crystals. With the OASLM powered, it is possible to retain the image without light. Prompt clearance of the OASLM requires an electrical signal. Optically addressed spatial light simulators are applicable in the second stage of very high-resolution display as computer generated holographic displays.
 
Images displayed on EASLMs can be transferred in a process known as active tiling to various parts on an OASLM. This happens before the entire image on the OASLM is viewed. EASLM run fast at about 2500 frames per second. Therefore, active tiling is possible with about 100 images on the EASLM transferred on to an OASLM without interfering full motion video display on the OASLM. It makes the images to have resolutions with more than 100 megapixels. 

Overall

Optical computing applications are not as flexible and programmable as digital options. Luckily, optical computing components such as SLMs are here to make inroads. These accessories make optical image processing systems more cost-effective and highly efficient.