Plenoptic Wavefront Sensing for Tactical Systems

Wavefront sensors for adaptive-optics systems have traditionally been used in conditions where atmospheric turbulence is relatively weak and concentrated near the pupil of the optical system. Recently, the need to perform adaptive optics compensation for strong and distributed turbulence has kindled interest in new wavefront sensor designs that must perform where the local rms wavefront gradients exceeds one wavelength per subaperture. In addition, new wavefront sensors are expected to operate passively, using information from a complex scene to determine the refractive distortion. Nanohmics has designed, fabricated, tested, and demonstrated a breadboard version of a new type of wavefront sensor that is suitable for the measurement of large wavefront figures resulting from distributed turbulence or large static aberrations. The sensor measures the wavefront error from observations of an extended scene, and is inherently immune to crosstalk between adjacent subapertures, even for very large local wavefront slopes. Nanohmics proposes to integrate a wavefront sensor on a Navy optical surveillance platform with a deformable mirror and associated optical components to demonstrate closed-loop adaptive-optics compensation of dynamic aberrations experienced by the telescope, platform window, and atmospheric turbulence during operations of the surveillance platform, resulting in improved ISR imagery.