New holographic gratings recorded in polymer-dispersed liquid crystals

Holographic gratings recorded in polymer-dispersed liquid crystals (H-PDLC) are very interesting as systems for electrically switchable diffractive devices. From the early 1990s, experiments, Bragg and Raman-Nath gratings are recorded in PDLC. A very thorough review of these investigations is published recently. In this paper we report our first experiments for H-PDLC gratings, recorded in two different optical arrangements using total internal reflection (TIR): 1) Stetson's scheme - when low and high spatial frequencies gratings are simultaneously recorded in the PDLC's volume, and 2) Nassenstein's scheme - when low or high spatial frequency grating is recorded with evanescent waves in very thin layer of the PDLC. A polarization grating recorded by the Stetson's scheme is also reported. The realtime diffraction efficiency dependence during the recording and the polarization characteristics are investigated.