Bidirectional Refractive-Index Programming via Three-Stage Sequential Thiol-Click Chemistry for High-Performance Holographic Recording
Abstract
Conventional holographic photopolymers (HPs) mainly rely on a polymerization–diffusion mechanism to record volume holographic gratings (VHGs), resulting in trade-offs among photosensitivity, refractive-index (RI) modulation (Δn), optical clarity, and VHG stability. To address these trade-offs, we propose a bidirectional refractive-index programming (BRIP) strategy based on three sequential thiol-click reactions. Stage I employs a base-catalyzed thiol–acrylate Michael addition to form a thiol-rich host matrix. Under holographic exposure, Stage II triggers photoinduced thiol–vinyl addition to incorporate a high-RI recording monomer into the bright regions, generating the initial VHG Δn while preserving residual thiol sites in the dark regions. After exposure, Stage III uses thermally activated thiol–epoxy addition to incorporate a low-RI enhancing monomer into these complementary dark regions, further increasing Δn. A representative BRIP HP formulation is developed to validate the strategy. Benefiting from the BRIP design, the material requires only 1.1–1.9 mJ/cm2 exposure dose to generate VHGs with initial Δn values of 0.0103–0.0232 after Stage II, which increase to 0.0193–0.0394 after Stage III, while maintaining >95% visible-light transmittance, <0.02% haze, and <4% Δn variation after ten thermal cycles between 200 and -197 °C. This work establishes a new molecular design paradigm for high-performance HPs.
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BibTeX
@misc{gao2026bidirectional,
title = {{Bidirectional Refractive-Index Programming via Three-Stage Sequential Thiol-Click Chemistry for High-Performance Holographic Recording}},
author = {Haoqiang Gao and Mingxuan Wang and Diqin Zhang and Yunlong Zhang and Qixin Zhou and Yong Bi and Yuxia Zhao},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009393/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009393/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Bidirectional Refractive-Index Programming via Three-Stage Sequential Thiol-Click Chemistry for High-Performance Holographic Recording
AU - Haoqiang Gao
AU - Mingxuan Wang
AU - Diqin Zhang
AU - Yunlong Zhang
AU - Qixin Zhou
AU - Yong Bi
AU - Yuxia Zhao
PY - 2026
DA - 2026/09/23
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009393/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009393/v1
AB - Conventional holographic photopolymers (HPs) mainly rely on a polymerization–diffusion mechanism to record volume holographic gratings (VHGs), resulting in trade-offs among photosensitivity, refractive-index (RI) modulation (Δn), optical clarity, and VHG stability. To address these trade-offs, we propose a bidirectional refractive-index programming (BRIP) strategy based on three sequential thiol-click reactions. Stage I employs a base-catalyzed thiol–acrylate Michael addition to form a thiol-rich host matrix. Under holographic exposure, Stage II triggers photoinduced thiol–vinyl addition to incorporate a high-RI recording monomer into the bright regions, generating the initial VHG Δn while preserving residual thiol sites in the dark regions. After exposure, Stage III uses thermally activated thiol–epoxy addition to incorporate a low-RI enhancing monomer into these complementary dark regions, further increasing Δn. A representative BRIP HP formulation is developed to validate the strategy. Benefiting from the BRIP design, the material requires only 1.1–1.9 mJ/cm2 exposure dose to generate VHGs with initial Δn values of 0.0103–0.0232 after Stage II, which increase to 0.0193–0.0394 after Stage III, while maintaining >95% visible-light transmittance, <0.02% haze, and <4% Δn variation after ten thermal cycles between 200 and -197 °C. This work establishes a new molecular design paradigm for high-performance HPs.
ER -