High efficiency programmable CGH using DMD generated masks

Computer Generated Holograms (CGHs) are used for wavefront shaping and complex optics testing. Present technology allows for recording binary CGHs. We propose a Digital Micro-mirror Device (DMD) as a reconfigurable mask, to record rewritable binary and grayscale CGHs on a photochromic plate. Opaque at rest, this plate becomes transparent when it is illuminated with visible light. We have successfully recorded the very first amplitude grayscale Fresnel CGH, with a contrast greater than 50, which was reconstructed with a high fidelity in shape, intensity, size and location. We propose a new Fourier CGH coding scheme leading to a quantification exceeding 1000 within a smaller cell size of 2x2 pixels. This code has been implemented for the BATMAN-instrument logo for visiting very different spatial frequencies. The CGH is recorded with our DMD-based set-up, leading to a 1000x1000 pixels hologram written on a photochromic plate. The reconstruction of the recorded images with a 632.8nm He-Ne laser beam and an imaging lens leads to images with a perfect fidelity in shape and intensity, for any single pixel of the original object. Our proposed code exhibits a much higher resolution, a better compacity and an increased throughput, in comparison with the current Fourier CGHs. These results reveal the high potential of this method for generating programmable/rewritable CGHs.