Fabrication of Multiplexed Computer Generated Volume Holograms in Photosensitive Glass

Abstract

We present a new approach for the fabrication of volume holograms in an optical nonlinear material with voxel sizes on the order of 1µm i.e., with increased degrees of freedom and thus improved multiplexing functionality.

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

“…In the current 3. Current State of the Art in Volume Holographic Optical Elements design approach [56,57], using Eqs. (3.14) and (3.16) optimization theory is applied to compute an optimal solution iteratively.…”

“…Current State of the Art in Volume Holographic Optical Elements (i) In the current state of the art the assumption of weak scattering is necessary in order to derive a linear model for the numerical modeling of the scattering process. Hereby the Born approximation is applied [56,57]. This approximation is derived by considering only linear perturbation of the amplitude of the scattered wave field.…”

“…Since the scattered field can be expected to increase with increasing distance of propagation, it is clear that the Born approximation can easily break down for large holograms. For holograms with dimensions in the sub-millimeter range, this assumption leads to a constraint that limits the index modulation allowed to very small values within a range on the order of (δ n ≈ 10 −4 • • • 10 −3 ), relative to the refractive index of the background material [56,57]. This in turn limits the optical functionality of the CGVH in terms of angular and frequency selectivity.…”

“…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.…”

“…This assumption leads to a constraint that limits the refractive index modulation allowed to very small values within a range on the order of δ n ≈ 10 −4 • • • 10 −3 , relative to the index of the background material [56,57]. This in turn limits the optical functionality of the CGVH in terms of angular and frequency selectivity, as well as the achievable SBWP.…”