Programmable diffractive optics for high-fidelity wavefront control

Abstract

High-fidelity wavefront control is demonstrated via programmable modulo-2π two-dimensional phase profiles displayed on a high-resolution computer-addressable phase modulator system. This prototype setup operates with 307,200 independently addressable elements and a fill-factor and interpixel influence function that are controlled via spatial filtering in a Fourier plane. Nonlinearities in the phase response are compensated computationally. Aberration compensation with better than 1/4-wave peak-to-peak fidelity is demonstrated."

Near-diffraction-limited compensated imaging and laser wavefront control with programmable diffractive optics

“…In order to investigate the fidelity of wavefront control with the PDO setup, described elsewhere, 7 we position a static glass plate aberrator in front of the PDO and perform interferometric measurements of a 532-nm wavefront reflected from the combined PDO/aberrator pair. The reflected light is then combined with a mutually coherent plane wave and relayed to a camera located in an image plane of the PDO phase modulating surface.…”

“…The maximum amount of combined tip and tilt in this figure is 100 waves at 532 nm. The decrease in brightness at the larger tilt values is an indication of the spatial-frequency dependence of the diffraction efficiency 7. Note that the a comparable result for tip and tilt operations could be achieved using two one-dimensional arrays of 2π phase modulators.…”

“…Namely, the diffractive losses associated with discrete element approximations to smooth phase profiles should be minimized, and for the case of near-diffraction-limited operation in the presence of large aberrations, the system should operate with high-dynamic range corresponding to both large-range phase compensation and high-fidelity wavefront control. Recently, 5,7 we presented an analysis and demonstration of a prototype architecture for programmable diffractive optics showing both high-optical efficiency and near-diffraction-limited compensated wavefront fidelity. The programmable diffractive optic (PDO) utilizes a commercial 640 x 480 element electrically addressed amplitude modulator, an optical Fourier filter, and a customized amplitude to phase converter.…”