Diffraction efficiency

About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.

Recording and fixing dynamics of nonvolatile photorefractive holograms in LiNbO 3 :Fe:Mn crystals

Abstract: A theoretical explanation of nonvolatile holographic recording in LiNbO3:Fe:Mn crystals is given based on jointly solving the two-center material equations and the coupled-wave equations The nonuniformity of the dynamics of the photorefractive grating can be effectively described and analyzed by using this method The time–space evolution, including the space-charge field, the diffraction efficiency, the light modulation depth, the phases of the space-charge field and the interference field, as well as the relative spatial phase shift between them, is studied for both oxidized and reduced crystals The optimal conditions for material prescriptions and oxidation–reduction processing are discussed in detail The bending isophase of the fringe pattern and the redistributed intensities of the two-coupled beams inside the crystal are presented The theoretical results can confirm and predict experimental results Some new effects are also discovered, such as: The fixed diffraction efficiency can exceed the saturation diffraction efficiency for strongly recorded gratings; the energy transfer direction between two-coupled beams can be reversed with crystal thickness; and the holographic readout in reduced crystal is always accompanied by fast phase changes, which results in the slow deterioration of the recorded holograms as a result of the production of homogeneous distributions of electrons

Fabricating and testing diffractive optical elements focusing into a ring and into a twin-spot

Abstract: We fabricated and experimentally studied diffractive optical elements intended to focus near IR light into a ring and a twin-spot Fabrication technology and the performances of the fabricated optical elements are discussed

Holographic transmission elements using improved photopolymer films

Abstract: Volume phase holographic gratings provide the high diffraction efficiency often required from holographic optical elements. In order to provide wide angular bandwidth, high index modulation is also required. A new addition to the family of Du Pont holographic photopolymer films has significantly higher index modulation for the grating spacings typical of holographic transmission elements. In this paper, the recording of volume phase transmission gratings in this holographic photopolymer is described. The dependence of holographic properties on exposure conditions, grating characteristics, and processing are discussed. The performance characteristics of holographic optical elements produced in this material are also presented.

A polarization insensitive 2×2 optical switch fabricated by liquid crystal–polymer composite

Abstract: A polarization insensitive 2×2 optical switch was fabricated with liquid crystal–polymer composite by means of holography. The highest diffraction efficiency achieved was 85.7%. The rise time and the decay time measured were 36 and 160μs, respectively, at an applied electric field of 18.2V∕μm. The polarization-dependent loss was 0.03dB measured for s- and p-polarized light at the wavelength of 632.8nm.

Diffractive optical modulator and method for producing the same

Abstract: The diffractive optical modulator of the invention includes: a plate having a portion functioning as a first electrode; a spacer layer formed on the plate; and a grating consisting of a plurality of beams having a portion functioning as a second electrode, both ends of the beams being supported on the spacer layer. In the diffractive optical modulator, by adjusting a voltage applied between the first electrode and the second electrode, a distance between the beams and the plate is varied, thereby controlling the diffraction efficiency. An insulating layer is further provided between the plate and the plurality of beams.