Invention:
This invention is a proprietary approach to realizing a reconfigurable computer generated hologram. This approach uses a spatial light modulator (SLM) to form a wavefront to correct for wavelength shift induced aberrations in volume holographic focusing elements.
Background:
Volume holographic optical elements show great potential for use in constrained applications like augmented and virtual reality eyewear since they can be realized with high diffraction efficiency in thin film materials. However, one of the problems with volume holographic materials is that they are only sensitive at shorter wavelengths (i.e. less than 650 nm) while many applications require operation at longer near IR wavelengths. When a focusing type holographic element is formed at one wavelength and reconstructed at a different wavelength, aberrations in the reconstructed image result from an inability to match the phase and Bragg conditions across the aperture of the hologram. Several methods have been proposed to correct this problem, although none completely successful. This invention proposes an alternative approach to solving this problem.
Applications:
- Constrained applications like augmented and virtual reality eyewear
Advantages:
- Reduced aberrations in reconstructed image
- Precise determination of aberrations through Bragg matching rays at the reconstruction wavelength geometry
- Meets the need for applications that require operation at longer near IR wavelengths
