Electrically controllable volume holographic apparatus and method for operating said apparatus

Claim 2

A volume holographic apparatus comprising a polar crystalline member of strontium barium niobate having the characteristic that coherently related reference and signal light beams angularly displaced from one another and incident on said crystalline member in at least partially super-imposed relationship establish refractive index inhomogeneities therein representative of the interference between said beams, and means for applying an electric potential to said member to establish an electric field therein oriented relative to the polar axis of said member so that said field and said light beams interact in said member to increase the sensitivity thereof to said light beams and thereby increase the amplitude of said refractive index inhomogeneities.

Claim 3

The apparatus of claim 1 wherein the strontium barium niobate has a composition SrxBa1 xNb2O6 with x having values in the range from .25 to .75.

Claim 6

The method of claim 3 wherein the storage medium is a poled crystalline member.

Claim 7

The method of claim 4 wherein the coherent beam of light is plane polarized parallel to the extraordinary index of the storage medium.

Claim 8

A holographic image reconstructing apparatus comprising a polar crystalline storage medium hAving an image representative pattern recorded therein in the form of refractive index inhomogeneities resulting from interference between a pair of coherently related light beams angularly displaced from one another and incident on the medium in at least partially superposed relation under the influence of an electric potential applied thereto for establishing an electric field in the medium oriented relative to the polar axis thereof so that the beams and the field interact to produce said inhomogeneities, means for illuminating the storage medium with a coherent reconstructing light beam having a propagational axis collinearly aligned with one of said recording beams, means for applying to said medium simultaneously with said reconstructing beam an electric potential for establishing in the medium an electric field oriented similarly to the field used in recording said inhomogeneities, and means for varying the amplitude of the applied electric potential to control the intensity of the reconstructed image whereby under a condition in which the electric potential is reduced to zero the image intensity reduces substantially to zero.

Claim 9

A holographic image reconstructing apparatus comprising a polar crystalline storage medium hAving an image representative pattern recorded therein in the form of refractive index inhomogeneities resulting from interference between a pair of coherently related light beams angularly displaced from one another and incident on the medium in at least partially superposed relation under the influence of an electric potential applied thereto for establishing an electric field in the medium oriented relative to the polar axis thereof so that the beams and the field interact to produce said inhomogeneities, means for illuminating the storage medium with a coherent reconstructing light beam having a propagational axis collinearly aligned with one of said recording beams, means for applying to said medium simultaneously with said reconstructing beam an electric potential for establishing in the medium an electric field oriented similarly to the field used in recording said inhomogeneities, and means for varying the amplitude of the applied electric potential to control the intensity of the reconstructed image whereby under a condition in which the electric potential is reduced to zero the image intensity reduces substantially to zero.

Claim 10

The apparatus of claim 6 wherein the storage medium exhibits ferroelectric properties.

Claim 11

The apparatus of claim 6 wherein the electric field is oriented parallel to the polar axis of the storage medium.

Claim 12

The apparatus of claim 6 wherein the propagational axis of the reconstructing beam is substantially transverse to the polar axis of the storage medium.

Claim 13

The apparatus of claim 6 wherein the reconstructing beam is plane polarized parallel to the extraordinary index of the storage medium.

Claim 14

The apparatus of claim 10 wherein the electric field is oriented parallel to the polar axis of the storage medium.

Claim 15

The apparatus of claim 11 wherein the propagational axis of the reconstructing beam is substantially transverse to the polar axis of the storage medium.

Claim 18

Apparatus for reconstructing an image from a hologram capable of being recorded in a polar crystalline storage medium as a pattern of refractive index inhomogeneities established therein by light beams, comprising means for illuminating the storage medium with a pair of coherently related light beams angularly displaced from one another and incident on said medium in at least partially superposed relation, means for applying to said member simultaneously with said pair of coherently related beams an electric potential for establishing in the medium an electric field oriented relative to the polar axis thereof so that the field and light beams interact to produce said reFractive index inhomogeneities for recording the hologram, means for illuminating the storage medium, subsequent to recording the hologram, with a coherent reconstructing light beam having a propagational axis collinearly aligned with one of said recording beams, means for applying to said medium simultaneously with said reconstructing beam an electric potential for establishing in the medium an electric field oriented similarly to the field used in recording the refractive index inhomogeneities, and means for varying the amplitude of the applied electric potential to control the intensity of the reconstructed image whereby under a condition in which the electric potential is reduced to zero the image intensity reduces substantially to zero.

Claim 19

Apparatus for reconstructing an image from a hologram capable of being recorded in a polar crystalline storage medium as a pattern of refractive index inhomogeneities established therein by light beams, comprising means for illuminating the storage medium with a pair of coherently related light beams angularly displaced from one another and incident on said medium in at least partially superposed relation, means for applying to said member simultaneously with said pair of coherently related beams an electric potential for establishing in the medium an electric field oriented relative to the polar axis thereof so that the field and light beams interact to produce said reFractive index inhomogeneities for recording the hologram, means for illuminating the storage medium, subsequent to recording the hologram, with a coherent reconstructing light beam having a propagational axis collinearly aligned with one of said recording beams, means for applying to said medium simultaneously with said reconstructing beam an electric potential for establishing in the medium an electric field oriented similarly to the field used in recording the refractive index inhomogeneities, and means for varying the amplitude of the applied electric potential to control the intensity of the reconstructed image whereby under a condition in which the electric potential is reduced to zero the image intensity reduces substantially to zero.