Compact Incoherent Multidimensional Imaging Systems Using Static Diffractive Coded Apertures

Abstract

Incoherent holographic imaging technologies, in general, involve multiple optical components for beam splitting—combining and shaping—and in most cases, require an active optical device such as a spatial light modulator (SLM) for generating multiple phase-shifted holograms in time. The above requirements made the realization of holography-based products expensive, heavy, large, and slow. To successfully transfer the holography capabilities discussed in research articles to products, it is necessary to find methods to simplify holography architectures. In this book chapter, two important incoherent holography techniques, namely interference-based Fresnel incoherent correlation holography (FINCH) and interferenceless coded aperture correlation holography (I-COACH), have been successfully simplified in space and time using advanced manufacturing methods and nonlinear reconstruction, respectively. Both techniques have been realized in compact optical architectures using a single static diffractive optical element manufactured using lithography technologies. Randomly multiplexed diffractive lenses were manufactured using electron beam lithography for FINCH. A quasi-random lens and a mask containing a quasi-random array of pinholes were manufactured using electron beam lithography and photolithography, respectively, for I-COACH. In both cases, the compactification has been achieved without sacrificing the performances. The design, fabrication, and experiments of FINCH and I-COACH with static diffractive optical elements are presented in details.