Enhancing Diffraction Efficiency in Polarization Volume Gratings via Polymer‐Stabilized Cholesteric Liquid Crystal Bilayers

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Bibliographic Details
Title: Enhancing Diffraction Efficiency in Polarization Volume Gratings via Polymer‐Stabilized Cholesteric Liquid Crystal Bilayers
Authors: Yu‐Chieh Chang, Ting‐Wei Gu, Yu‐Chieh Li, Ta‐Lung Chang, Chun‐Ta Wang
Source: Advanced Materials Interfaces. 12
Publisher Information: Wiley, 2025.
Publication Year: 2025
Description: Polarization volume gratings (PVGs), formed using patterned cholesteric liquid crystals (CLCs), offer high diffraction efficiency, polarization selectivity, and broad angular bandwidth—making them ideal for advanced photonic applications. However, traditional CLC‐based PVGs are intrinsically limited to a maximum reflectivity of 50% for unpolarized light, capping their diffraction efficiency. To overcome this limitation, a recently proposed approach is presented that achieves hyper‐reflectivity in a single polymer‐stabilized cholesteric liquid crystals CLC (PSCLC) cell using a bilayer helical structure fabricated via photo‐polymerization‐enforced stratification (PES). This method enables the coexistence of two CLC layers with orthogonal helical handedness, facilitating reflection of both left‐ and right‐handed circularly polarized light. Experimental results confirm that through precise material composition and photo‐polymerization processing, PVGs with either multi‐band reflection or high diffraction efficiency can be realized. Moreover, the bilayer architecture exhibits tunable optical behavior under electric fields and temperature variation, underscoring its potential in adaptive and reconfigurable optical systems.
Document Type: Article
Language: English
ISSN: 2196-7350
DOI: 10.1002/admi.202500396
Rights: CC BY
Accession Number: edsair.doi...........ebf86d516f5bb501eb84f444fd5a55ee
Database: OpenAIRE
Description
Abstract:Polarization volume gratings (PVGs), formed using patterned cholesteric liquid crystals (CLCs), offer high diffraction efficiency, polarization selectivity, and broad angular bandwidth—making them ideal for advanced photonic applications. However, traditional CLC‐based PVGs are intrinsically limited to a maximum reflectivity of 50% for unpolarized light, capping their diffraction efficiency. To overcome this limitation, a recently proposed approach is presented that achieves hyper‐reflectivity in a single polymer‐stabilized cholesteric liquid crystals CLC (PSCLC) cell using a bilayer helical structure fabricated via photo‐polymerization‐enforced stratification (PES). This method enables the coexistence of two CLC layers with orthogonal helical handedness, facilitating reflection of both left‐ and right‐handed circularly polarized light. Experimental results confirm that through precise material composition and photo‐polymerization processing, PVGs with either multi‐band reflection or high diffraction efficiency can be realized. Moreover, the bilayer architecture exhibits tunable optical behavior under electric fields and temperature variation, underscoring its potential in adaptive and reconfigurable optical systems.
ISSN:21967350
DOI:10.1002/admi.202500396