Forming and reading holograms
First Claim
1. A method of forming and reading a hologram comprising:
- directing recording beams of coherent electromagnetic radiation at a recording first frequency (and corresponding first wavelength in free space) into a first medium, having a first index of refraction, and therethrough at a recording second wavelength, and onto a surface of said first medium positioned contiguous to a surface of a recording second medium, having a second index of refraction, to form an interference pattern in both of said media, the pattern being continuous across the boundary between the two media;
developing the recording second medium to produce a hologram therein; and
directing a reconstructing beam of coherent electromagnetic radiation at a reconstruction second frequency that is lower than the recording first frequency (and corresponding third wavelength in free space that is longer than the said first wavelength) into a third medium having a third index of refraction, that is higher than said first index of refraction, and therethrough onto a surface of said third medium positioned contiguous to a surface of the second medium at or parallel to the said boundary, and into said second medium to read the hologram at the said recording second wavelength.
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Accused Products
Abstract
A method of forming and reading a hologram, useful for instance as a lens, is disclosed which eliminates chromatic aberrations usually present when a hologram is recorded using light of a higher frequency than that for which the hologram is to be used on reconstruction. The fringes created by the interference of two beams of radiation at the recording frequency in a first medium are transferred to a recording second medium by virtue of the second medium having a surface contiguous to the fringes in the first medium. The second medium is then developed to produce a hologram. A reconstruction beam from a laser having a lower frequency than that of the recording beams is directed at a third medium which is contiguous to a surface of the hologram so as to cause the wavelength of the read-out beam to equal that of the recording beams.
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Citations
17 Claims
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1. A method of forming and reading a hologram comprising:
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directing recording beams of coherent electromagnetic radiation at a recording first frequency (and corresponding first wavelength in free space) into a first medium, having a first index of refraction, and therethrough at a recording second wavelength, and onto a surface of said first medium positioned contiguous to a surface of a recording second medium, having a second index of refraction, to form an interference pattern in both of said media, the pattern being continuous across the boundary between the two media; developing the recording second medium to produce a hologram therein; and directing a reconstructing beam of coherent electromagnetic radiation at a reconstruction second frequency that is lower than the recording first frequency (and corresponding third wavelength in free space that is longer than the said first wavelength) into a third medium having a third index of refraction, that is higher than said first index of refraction, and therethrough onto a surface of said third medium positioned contiguous to a surface of the second medium at or parallel to the said boundary, and into said second medium to read the hologram at the said recording second wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification