Electro-optic properties of switchable gratings made of polymer and nematic liquid-crystal slices.
We report the diffraction properties at wavelengths of 632.8 and 1550 nm for volume transmission gratings made of a sequence of continuously aligned nematic liquid-crystal layers separated by isotropic polymer slices. The gratings are generated by holographically curing a solution of liquid crystal diluted in an isotropic prepolymer by means of a laser beam at a wavelength of 352 nm with a total intensity of approximately 10 mW/cm2. A diffraction efficiency of 98% was measured, and an electric field as low as 5 V/microm switches off the phase grating. Measured angular spectra are fitted by use of the modified coupled-mode theory including the effects of grating birefringence.
d'Alessandro
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Department of Electronic Engineering, University of Rome La Sapienza, National Institute for the Physics of Matter, Via Eudossiana 18, 00184 Rome, Italy. antonio.dalessandro@uniroma1.it
Asquini
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Gizzi
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Caputo
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Umeton
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Veltri
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Sukhov
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