Design and optimization of programmable lens array for adaptive optics

Abstract

The ability of a liquid-crystal spatial light modulator (LC-SLM) to generate lens and lens arrays of variable focal lengths and selectable fields of view (FOV) makes them excellent candidates for many adaptive optics applications including free-space optical telecommunications, astronomy and retinal imaging. In this paper, we report a range of dynamic lens and lens array designs and optimization using a LC-SLM as an adaptive Hartmann-Shack wavefront sensor. The measured wavefront aberration is reconstructed using Zernike polynomials through the application of its conjugated wavefront onto the LC-SLM to achieve dynamic wavefront detection and correction. Computer algorithms based on Fourier transformation for lens synthesis have been developed to address the LC-SLM and to generate appropriate phase holograms that emulate lens and/or lenslet arrays with programmable focal lengths, tilting angles and diameters. The classic least-square (LS) method is used to determine the Zernike polynomial coefficients for the reconstruction of the aberrated wavefront. Experimental results demonstrate the dynamic generation of lens arrays of variable focal lengths. We also experimentally characterize the phase modulation performance and wavefront generation performance of the LC-SLM through the application of Zernike functions and as diffractive optical elements (DOEs) for dynamic wavefront generation.