title: Restoration of broadband imagery steered with a liquid-crystal optical phased array
abstract: In many imaging applications, it is highly desirable to replace mechanical beam-steering components (i.e., mirrors and gimbals) with a nonmechanical device. One such device is a nematic liquid crystal optical phased array (LCOPA). An LCOPA can implement a blazed phase grating to steer the incident light. However, when a phase grating is used in a broadband imaging system, two adverse effects can occur. First, dispersion will cause different incident wavelengths arriving at the same angle to be steered to different output angles, causing chromatic aberrations in the image plane. Second, the device will steer energy not only to the first diffraction order, but to others as well. This multiple-order effect results in multiple copies of the scene appearing in the image plane. We describe a digital image restoration technique designed to overcome these degradations. The proposed postprocessing technique is based on a Wiener deconvolution filter. The technique, however, is applicable only to scenes containing objects with approximately constant reflectivities over the spectral region of interest. Experimental results are presented to demonstrate the effectiveness of this technique
keyphrases: broadband imagery optical phased array imaging applications mechanical beam-steering components mirrors gimbals nonmechanical device nematic liquid crystal optical phased array blazed phase grating broadband imaging system dispersion incident wavelengths output angles chromatic aberrations image plane first diffraction order multiple-order effect multiple copies digital image restoration technique postprocessing technique Wiener deconvolution filter approximately constant reflectivities spectral region of interest liquid-crystal optical phased array steering incident light steering halogen lamp