Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers

Abstract

Although the angular distribution of noise gratings in holographic photopolymer is understood to arise from Bragg matching, the details of scatter strength and dynamics are not fully understood. This confounds development of materials and recording techniques that minimize haze. Here, the kinetics are studied using a multi-physics numerical approach coupling diffraction of light from the dynamic material including scatter centers, reactions of chemical species initiated by this light, diffusion and swelling of these constituents, and the formation of the refractive index from the resulting composition. The approach is validated in the case of two-beam transmission holography by comparison to traditional harmonic series and rigorous coupled-mode approaches. Two beam holography in the presence of scatter is then used to study haze development. This reveals that haze due to weak noise gratings grows significantly above initial scatter only in reaction-limited materials, consistent with proposed Bragg-matched amplification mechanisms. Amplified haze is found to be proportional to initial scatter, quantifying the impact of clean sample fabrication. Conversely, haze is found to grow super-linearly with sample thickness, illustrating the significant challenge for applications requiring low haze in large thickness.

Influence of Pre-Exposure on the Material Response of Epoxy-Based Volume Holographic Recording Material

“…Diffusion models are then used for this purpose [ 14 , 15 ]. This also includes studying the dynamics of noise gratings with the goal of developing material formulations and processing methods that result in high signal-to-noise ratios [ 16 ]. It should be noted that the individual factors can also influence each other [ 17 ].…”

Editorial for the Special Issue “Polymeric and Polymer Nanocomposite Materials for Photonic Applications”

“…R. R. McLeod presents a study about noise gratings dynamics in holographic photopolymers [ 1 ]. The numerical approach is validated in the case of two-beam transmission holography in comparison to traditional harmonic series and rigorous coupled-mode approaches.…”