Volume phase reflection holograms and methods for fabricating them
First Claim
1. A volume phase reflection hologram comprising a volume phase medium having formed therein a surface relief structure for use in wavefront reconstruction, said surface relief structure comprising a plurality of neighboring terraced depressions whose terraces are located depthwise in said medium substantially at interference planes.
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Accused Products
Abstract
A hologram is fabricated by opening a volume phase reflection hologram formed in a recording medium such as a positive photoresist. The opening occurs by forming a second hologram, such as an off-axis hologram, in the same recording medium. The opened hologram can be replicated in metal and the metal can be used to emboss the fringe pattern of the opened hologram into plastic. A full range of colors in the visible spectrum may be obtained by metallizing the embossed plastic structure and then by overcoating it with appropriate clear dielectric layers.
110 Citations
10 Claims
- 1. A volume phase reflection hologram comprising a volume phase medium having formed therein a surface relief structure for use in wavefront reconstruction, said surface relief structure comprising a plurality of neighboring terraced depressions whose terraces are located depthwise in said medium substantially at interference planes.
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10. A volume phase reflection hologram comprising a holographic phase medium having exterior surfaces and a given thickness, said holographic phase medium having formed therein two sets of interference fringes, one of said sets of interference fringes having planes of maximum and minimum intensity substantially perpendicular to said surfaces and having a predetermined periodicity and the other set of planes having planes of maximum and minimum intensity substantially parallel said medium surfaces and of finer periodicity than that of said predetermined periodicity of said perpendicular fringes, both said parallel and perpendicular interference fringes combining to provide a joint fringe pattern in said medium that varies both over the surface and depth of said medium in the form of a plurality of terraced depressions whose terraces are distributed depthwise in the medium substantially at the locations of said parallel fringes.
Specification