Spectral-envelope modulated double-phase method for computer-generated holography.

Computer-generated holography provides an approach to modulate the optical wavefront with computationally synthesized holograms. Since the hardware implementation for complex wavefronts is not yet available, double-phase decomposition is utilized as a complex encoding method of converting a complex wavefront to a double-phase hologram. The double-phase hologram adapts a complex wavefront for the phase-type devices, but the reconstruction is plagued by the noise caused by spatial-shifting errors. Here, a spectral-envelope modulated double-phase method is proposed to suppress the spatial-shifting noise with an off-axis envelope modulation on the Fourier spectrum of a double-phase hologram. This proposed method out-performs conventional on-axis double-phase method in optical reconstructing accuracy with indicated 9.54% improvement in PSNR and 196.86% improvement in SSIM.