Design of cubic-phase optical elements using subwavelength microstructures.

We describe a design methodology for synthesizing cubic-phase optical elements using two-dimensional subwavelength microstructures. We combined a numerical and experimental approach to demonstrate that by spatially varying the geometric properties of binary subwavelength gratings it is possible to produce a diffractive element with a cubic-phase profile. A test element was designed and fabricated for operation in the LWIR, approximately lambda=10.

Evolutionary paths in imaging and recent trends.

An examination of recent trends in imaging reveals a movement toward systems that balance processing between optics and electronics. Imaging applications include conventional imaging to produce visually pleasing images, special purpose imaging whose output is also an image but with enhanced characteristics, and functional imaging to produce information about a scene from optical data. We identify three approaches to computational imaging that are capable of achieving these goals: wavefront encoding, multiplex imaging, and feature extraction.