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

Dynamic wave field synthesis: enabling the generation of field distributions with a large space-bandwidth product

“…Computer generated volume holograms are volumetric holographic non-periodic optical elements whose complex transfer functions can be controlled and optimized in the design process [47,56]. In analogy to their 2D counterparts (cf.…”

“…The first computer generated volume hologram was proposed as a specific type of modulated three dimensional grating a few decades ago [54] and has been investigated continuously since then [55,56]. Recently, we have in our previous work studied and demonstrated their superior performance in terms of angular and wavelength multiplexing [47,57]; as well as their application in the dynamic synthesis of wave fields [17]. State of the art CGVHs can be described as volumetric holographic optical elements whose complex transfer functions can be controlled and optimized in the design process.…”

Fabrication of Multiplexed Computer Generated Volume Holograms in Photosensitive Glass

“…In the recent past, major focus has been on 3D diffractive and holographic optical elements, which offer more degrees of freedom as opposed to their 2D counterparts [1,2]. For instance, computer generated volume holograms (CGVH) with angular and frequency multiplexing capabilities have recently been demonstrated [3].…”

“…In order to fabricate devices with advanced functionalities, e.g. for applications in wavefield synthesis [2], voxel sizes on the order of ∆v ≈ 1µm are necessary [3] since this leads to devices with more degrees of freedom and to reduced cross talk between single projections in multiplexed devices. Such focal volume sizes are however beyond the current capabilities of linear absorption based laser direct writing, whereby voxel sizes on the order of ∆v = 2µm have been reported [3].…”

“…Furthermore, we propose an iterative simulated annealing algorithm (SAA) for the design of the CGVHs, whereby a binary constraint which is inherently imposed by the fabrication process is integrated directly into the design. This global approach, as opposed to the commonly applied projection onto convex sets (POCS) method [2], helps avoid convergence to an arbitrary local minimum. To verify the refractive index change induced in the glass, a novel computational shear interferometry based differential interference contrast (DIC) microscope was applied [5].…”