<title>Near-IR (800 to 855 nm) sensitive holographic photopolymer-dispersed liquid crystal materials</title>

Abstract

H-PDLC materials are introduced with sensitivity in the 800- 850 nm region. Materials presented are based on acrylate monomers mixed with liquid crystalline (LC) compounds and sensitized to near IR. This allows highly efficient in-situ recording of holographic optical elements by diode lasers. Various LC compounds have been tested, in particular: E7, 5CB, MBBA. The following parameters of the H-PDLC materials and the recorded gratings were investigated: sensitivity of the materials in the range 800-850 nm, diffraction efficiency in a wide range of wavelengths and photochemical stability of the recorded gratings. The sensitivity of the materials with LCs E7 and 5CB was found to be ca. 300-500 mJ/cm2 to wavelengths 834 and 850 nm. Employment of MBBA led to drop in sensitivity of about an order of magnitude. High diffraction efficiency was demonstrated. Particularly interesting are the following properties of our materials: (1) Control of the dispersion of the diffraction efficiency for p-polarization is shown to be possible by changing the monomer content of the formulations. (2) Recorded gratings exhibit excellent photochemical stability. (3) Switching of the gratings is in principle possible and currently worked on.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.