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/cm<sup>2</sup> . A diffraction efficiency of 98% was measured, and an electric field as low as 5 V/μm switches off the phase grating. Measured angular spectra are fitted by use of the modified coupled-mode theory including the effects of grating birefringence.
© 2004 Optical Society of America
A. d'Alessandro, R. Asquini, C. Gizzi, R. Caputo, C. Umeton, A. Veltri, and A. V. Sukhov, "Electro-optic properties of switchable gratings made of polymer and nematic liquid-crystal slices," Opt. Lett. 29, 1405-1407 (2004)