Application Research And Performance Enhancement Of Dichromated Gelatin Holographic Recording Material

Dichromated gelatin (DCG) has excellent holographic recording performances such as high diffraction efficiency, high spatial resolution, high signal-to-noise ratio, etc., and has been developed into an important recording material for image display and holographic optical elements. As a promising holographic optical element, the Lippmann- type holographic reflector has found good applications as holographic notch filter, holographic beam-splitter mirror, solar energy concentrator, and single-channel wavelength selector in wavelength-multiplexed optical fiber communication system, etc.In this thesis, the red—sensitized gelatin recording materials with high imaging speed and photo —sensitivity are obtained by optimizing material recipe and post — processing procedures. The holographic volume gratings and reflection holograms having high diffraction efficiencies and signal —noise ratio are also fabricated experimentally. Meanwhile, the imaging mechanism of this optimized recipe is also discussed.In addition, a new technique was presented for adjusting the playback wavelength of Lippmann holograms recorded in methylene-blue sensitized dichromated gelatin (MBDCG). The main feature of this technique is introducing a water-soluble organic reagent into MBDCG photosensitive layer as preswelling reagent and wavelength adjuster. This method has wide wavelength adjustment range (up to 200 nanometers) and high signal-to-noise ratio, can be applied to quantitatively adjust the playback wavelength of reflection hologram by changing the concentration of preswelling reagent. Its possible applications includecolor image display, holographic optical elements, and optical anti-counterfeiting.We also did some new research in color holography on basis of MBDCG. By employing new types of multi-color photosensitizers and photochemical promoters to photo-crosslinking gelatin system, a high-quality single-layer panchromatic dichromated gelatin material is achieved for color holography. It has wide spectral response within the visible light region, high spatial resolution up to 20mj/cm2 for three-primary-color laser lines, high diffraction efficiency up to 85%, and high spatial resolution up to 40001ines/mm, ect. The Lippmann color holograms with high color saturation, high brightness and low noise are recorded successfully. It can be expected to have practical applications in the fields of true-color display holography, wavelength multiplexing holographic storage, and holographic optical elements.