An investigation of the array-tilt aberration for hexagonal, optical phased arrays is presented. The investigation begins with theoretical derivations of the far-zone radiated field, the array factor, and the far-field radiated power for the seven-element hexagonal array with array tilt present. Physical insights gained from this analysis are discussed. An analytical treatment of correlation-based array-tilt estimators is also undertaken. Two novel array-tilt estimation techniques are developed from the analysis. The new techniques are shown to be significantly more efficient computationally than the traditional estimation approach. Simulation and experimental results are presented to validate the new array-tilt estimation methods.

A conceptual system capable of detecting the occurrence of stair mode across an optical array has been developed and studied. This conceptual system utilizes a single camera, referred to as the stair mode imager, to image the irradiance pattern produced at the target. The collected image is then cross-correlated with a database of theoretical stair mode images to estimate the amount of stair mode across the array. Previous studies have been limited to computer simulations and are expanded here into hardware-based experimentation. These experiments further study the effects of stair mode and are aimed at validating previous simulation findings and further characterizing the ability and constraints of the stair mode imager.