UV beam-assisted efficient formation of surface relief grating on azobenzene polymers
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An efficient method is demonstrated to improve the formation of a surface relief grating (SRG) with a high amplitude. The SRG is realized by a two-beam interference technique (λ=532 nm) in an azobenzene side-chain copolymer. An UV laser beam (λ=355 nm), called assisting beam, was used to accelerate the photoisomerization process from cis-form to trans-form, resulting in a rapid cis-form ⇌ trans-form cycle. This UV beam-assisted method allowed to increase the diffraction efficiency of the formed SRG as well as its depth. Stable gratings with modulation depth as high as 410 nm were obtained at room temperature with moderate laser power.
KeywordsDiffraction Efficiency Wave Plate Holographic Data Storage Writing Beam Polarization Configuration
We are grateful to J. Lautru and A. Brosseau for invaluable help and access to the cleaning room and atomic force microscope. We also thank M. Dumont for useful discussion about the absorption spectra measurement technique. This work was partially supported by Institute d’Alembert of the ENS Cachan.
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