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Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers

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 a...

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Autor principal: McLeod, Robert R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699332/
https://www.ncbi.nlm.nih.gov/pubmed/33228025
http://dx.doi.org/10.3390/polym12112744
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author McLeod, Robert R.
author_facet McLeod, Robert R.
author_sort McLeod, Robert R.
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description 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.
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spelling pubmed-76993322020-11-29 Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers McLeod, Robert R. Polymers (Basel) Article 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. MDPI 2020-11-19 /pmc/articles/PMC7699332/ /pubmed/33228025 http://dx.doi.org/10.3390/polym12112744 Text en © 2020 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
McLeod, Robert R.
Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title_full Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title_fullStr Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title_full_unstemmed Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title_short Numerical Technique for Study of Noise Grating Dynamics in Holographic Photopolymers
title_sort numerical technique for study of noise grating dynamics in holographic photopolymers
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699332/
https://www.ncbi.nlm.nih.gov/pubmed/33228025
http://dx.doi.org/10.3390/polym12112744
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