Optical EngineeringNonmechanical microscanning using optical space-fed phased arrays
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A method for microscanning in imaging sensors is developed that allows liquid-crystal beam steerers to be used as nonmechanical microscan devices. This submicroscanning method involves using the beam steerers to shift images on a focal-plane array by a fraction of the amount used in typical microscan methods. Interpolation techniques based on interlaced sampling are used to produce images free of aliasing out to twice the Nyquist frequency determined by the focal-plane array. Since a continuous phase ramp is produced by the liquid-crystal beam steerer, dispersion effects due to the gratinglike nature of the devices are avoided. Simulations for both one- and two-dimensional cases are presented, as well as experimental results using a 3- to 5-μm imaging sensor and a liquid-crystal beam steerer designed for operation at 1.064 μm.