A new approach to dynamic wave field synthesis using computer generated volume holograms

Abstract

We present a novel design of an angular multiplexed system that facilitates dynamic synthesis of predefined wave fields using a 3D diffractive optical element. In this system several angular projections of given far-field intensities are encoded in a single computer generated volume hologram (CGVH). A spatial light modulator (SLM) is used to modulate an impinging plane reference wave thus allowing a dynamic decoding of individual projections. This also facilitates decoding a linear combination of various projections and can therefore be applied to synthesize wave fields with a much higher spatial-band-width-product as compared to conventional 2D static diffraction optical elements. We propose a 3D laser lithography based fabrication of these holograms in polymers and have thus incorporated corresponding fabrication constraints in the design process. Through numerical simulation of propagation through the system, initial feasibility studies have been undertaken. The obtained results show superior properties in terms of diffraction efficiency and angular selectivity as compared to cascaded optical elements.