Laser Application and Sparse Imaging Analysis of Diffractive Optical System

Abstract

In recent years, the diffractive optical systems have developed rapidly. Diffractive devices such as binary optical device and membrane-based lens are equivalent to fixed phase shifters of microwave antennas. Thus, the mature theories and methods of a microwave phased-array antenna could be used for diffractive devices’ performance analysis. Both laser Synthetic Aperture Radar (SAR) and laser communication feature a single color and long wavelength, and they are specifically suitable for non-imaging diffractive optical systems. A signal wave front control realized by a diffraction device reduces the focal length and the weight of a system. Research on laser SAR and laser communication technology has important theoretical significance and application value for diffractive optical system. In this paper, we provide a phased-array interpretation of a diffractive optical system and introduce research that has been conducted on airborne and spaceborne laser SAR with respect to diffractive optical systems. We propose the concept of shipborne 1 m diffraction aperture laser communication and an interferometric positioning system and analyze its performance. The results indicated that, using a 10 m short baseline, this system can reach 400 million km with a corresponding positioning accuracy of 6 km that is suitable for use during deep space probes. We also discuss the sparsesampling laser-imaging problem using a laser to illuminate the target, transforming the laser image signal into the frequency domain with Fourier lens, using the small-scale detector to perform sparse sampling in the lowfrequency domain, and reconstructing the target image using a computer. Some preliminary simulation results are provided.

Keywords

• diffractive optical system
• lidar
• laser communication
• synthetic aperture imaging
• interferometric angular positioning
• sparse imaging