Optimization-Based Adaptive Optical Correction for Holographic Projectors

A novel method of correcting the aberrations of holographic projectors is presented. The method employs an optimization algorithm to determine an aberration-correcting phase mask composed of 13 Zernike Polynomials. The mask can be used thereafter to correct every image produced by the projector. Two optimization algorithms are demonstrated: a hybrid genetic steepest descent algorithm and a heuristic variant of steepest descent. The primary advantage of these methods is that no modifications of the standard holographic projector are required. Furthermore, the methods are fully automated. They are evaluated on two projectors with different Spatial Light Modulator flatness profiles for three wavelengths. First, the correction is demonstrated for both projectors on a green wavelength. It is then adapted for red and blue wavelengths by rescaling the mask and adjusting for chromatic aberration. The hybrid genetic-steepest-descent algorithm is compared with the heuristic steepest descent algorithm. On average, the hybrid algorithm is found to give better and more reliable correction than the heuristic steepest descent algorithm while taking 50% longer to terminate. The method is also compared with nonautomated interferometric flatness measurements and is found to produce improved results.