Holographic Imaging

Lower Cost, Lower Power

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Computer Generated Holography involves the calculation of a holographic interference pattern, which can be used to project a 2D image or pattern using a laser. Iterative algorithms exist that allow phase-only interference patterns to be calculated, and these can be used to modulate laser light in real time using reflective LCOS devices.

Applications include low power, light weight projectors and head-up displays. The advantages of using phase modulation over amplitude modulation are:

Lower power: Improved optical efficiency gives brighter output using lower power lasers

Lower cost: Fewer optical components are required and a small number of dead pixels in the LCOS do not affect the image output.

Improved reliability: No moving parts, Laser light sources, graceful image degradation with dead pixels in the LCOS

Three lasers can be used to produce colour images with a wider colour gamut than traditional projectors.

The calculation of the phase-only interference pattern requires iteration using 2D Fourier Transforms. The FFT performance of the CSX700 enables a larger number of iterations for each frame, giving a high quality, high frame rate output when running in real time. For example, a single CSX700 can generate high quality head-up display patterns at 60Hz, and high quality images at 30Hz. ClearSpeed are able to demonstrate this technology using an LCOS device from Holoeye Photonics.

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Two research groups have successfully used ClearSpeed technology to accelerate their holographic applications.