Dichromated gelatin for the fabrication of holographic optical elements

Abstract

Hardened dichromated gelatin is the best material available today for the fabrication of holographic optical elements (HOEs) because of its low scattering, large refractive index modulation capacity, and other unique properties such as reprocessibility. On the basis of experimental data accumulated during the last several years, we describe holographic characteristics of the dichromated gelatin, including exposure characteristics with a bulk exposure model, hologram thickness change, and environmental stability. Basic chemistry, hologram formation in the dichromated gelatin, and generalized processing techniques are also discussed.

Computer Generated Holographic Optics.

“…By using a volume phase material, such as dichromated gelatin 8 for the HOE, diffraction efficiencies approaching 100% are achieved and spurious orders of diffraction are minimized. By combining appropriate optics with the CGH in the recording beam, the resolution and the space-bandwidth product required of the CGH can be greatly reduced.…”

<title>Silver-Halide Gelatin Holograms</title>

“…Assuming that the front and rear surface reflection loss was about 7%, we can easily find that the average absorption was about 18%. This absorption was primarily due to the stain caused by the reaction products such as CrBr 3 .…”

“…MajorLIN advatage ofM sive-ald gelatin hoo2.s r wid spectral resons an6oe8epsr0eqieet The dichromated gelatin process can produce nearly ideal holograms which have high diffraction efficiency and little scattering and absorption [1][2][3]. However, dichromated gelatin has two basic drawbacks.…”

Polymerizable Materials for Diffractive Optical Elements Recording

“…The holographic recording materials change their properties when they are exposed to the light, and there are many examples of them, for example, the photographic emulsions [9], photochromic materials [10], dichromated gelatin [11], photorefractive materials [12], or photopolymers [13].…”