Mechanical deformation of a liquid crystal diffraction grating in an elastic polymer

✍ Scribed by Michael E. De Rosa; Vincent P. Tondiglia; Lalgudi V. Natarajan

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 217 KB
• Volume: 68
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980425)68:4<523::aid-app2>3.0.co;2-o

✦ Synopsis

We demonstrate the tuning of the diffraction efficiency in a polymer-dispersed liquid crystal (PDLC) diffraction grating by mechanical shear deformation. We chose a photocurable thermoset with elastic mechanical properties as the host material to demonstrate the tuning effect. Raman-Nath gratings were prepared by anisotropically curing a mixture of commercial photopolymer doped with liquid crystal. The mixture was contained between glass slides which were mounted in a simple shearing device. During the photopolymerization, the liquid crystal phase separated into 2-mm droplets organized into channels with 3.8-mm spacing. Gratings were deformed by shearing the samples in a direction perpendicular to the channel orientation. The diffraction intensity and morphology were monitored as a function of shear strain. Reversible tuning was observed due to the elastic nature of the matrix.