Laser spatial coherence compensation in holography

Claim 3

A method according to claim 1 wherein the step of diffusing the light beam includes placing a diffusive medium in the light beam between the laser and the object scene.

Claim 4

A method according to claim 1 wherein the step of diffusing the light beam includes placing an opal glass diffusive medium in the light beam between the laser and the object scene.

Claim 5

A method according to claim 1 wherein the step of diffusing the light beam includes placing a ground glass diffusive medium in the light beam between the laser and the object scene.

Claim 6

A method according to claim 1 wherein the step of placing a hologram detector includes placing a photographic film in the light beam after modification by the object scene.

Claim 7

A method according to claim 1 wherein the step of directing a light beam from a laser includes pulsing a solid state laser to produce the light beam.

Claim 8

Apparatus for constructing a hologram of an opaque diffusely reflecting object scene, comprising: a laser light source having a light beam ouput with a plurality of transverse modes, a hologram detector, means for directing a portion of the intensity of said beam onto said opaque diffusely reflecting object scene for reflection therefrom as an object modified beam onto said detector and for diverting another portion of the intensity of said beam directly onto said detector as a reference beam for interference with the object modified beam, and means in the object beam between said laser and said object scene for diffusing said object beam so that substantially all illuminated points of the object scene are each illuminated by every transverse mode of said laser light output.

Claim 9

Apparatus for constructing a hologram of an opaque diffusely reflecting object scene, comprising: a laser light source having a light beam ouput with a plurality of transverse modes, a hologram detector, means for directing a portion of the intensity of said beam onto said opaque diffusely reflecting object scene for reflection therefrom as an object modified beam onto said detector and for diverting another portion of the intensity of said beam directly onto said detector as a reference beam for interference with the object modified beam, and means in the object beam between said laser and said object scene for diffusing said object beam so that substantially all illuminated points of the object scene are each illuminated by every transverse mode of said laser light output.

Claim 10

Apparatus according to claim 7 wherein said means for diffusing the laser light beam includes ground glass.

Claim 11

Apparatus according to claim 7 wherein said means for diffusing the laser light beam includes opal glass.

Claim 12

Apparatus according to claim 7 wherein said hologram detector includes photographic sensitive film.

Claim 13

Apparatus according to claim 7 wherein said laser light source includes a pulsed solid state laser.

Claim 14

Apparatus according to claim 7 wherein said laser light source includes a pulsed ruby laser.

Claim 17

In a method of constructing an off-axis hologram with a coherent light beam having a plurality of transverse modes in which a portion of the light beam intensity illuminates an object scene to produce an object modified beam and the remaining portion of the light beam intensity directly illuminates as a reference beam a photosensitive hologram detector positioned in the path of the object modified beam, said reference beam illuminating at least one area of the hologram detector with light of less than all of the plurality of transverse modes present in said coherent light beam, the improvement which includes illuminating the object scene in a manner that substantially all illuminated points thereof receive light of each of said plurality of transverse modes from said coherent light beam, aNd wherein at least a portion of the object scene is characterized by its illuminated portion being diffusely reflective and wherein the object modified beam is formed by reflection of the object illumination from the object scene.

Claim 18

In a method of constructing an off-axis hologram with a coherent light beam having a plurality of transverse modes in which a portion of the light beam intensity illuminates an object scene to produce an object modified beam and the remaining portion of the light beam intensity directly illuminates as a reference beam a photosensitive hologram detector positioned in the path of the object modified beam, said reference beam illuminating at least one area of the hologram detector with light of less than all of the plurality of transverse modes present in said coherent light beam, the improvement which includes illuminating the object scene in a manner that substantially all illuminated points thereof receive light of each of said plurality of transverse modes from said coherent light beam, aNd wherein at least a portion of the object scene is characterized by its illuminated portion being diffusely reflective and wherein the object modified beam is formed by reflection of the object illumination from the object scene.

Claim 19

A holographic apparatus having improved spatial coherence and uniform amplitude distribution comprising: a. a solid laserable material; b. means for pumping said laserable material into an excited stage; c. a resonant cavity enclosing said laserable material to cause the generation of a pulse of a substantially monochromatic, coherent light beam; d. a mode selector in said cavity for permitting a light pulse of substantially a single frequency to be built up, while providing substantially no transverse mode selection; e. optical means for splitting said light beam into a scene beam and a reference beam; f. a recording material disposed in a predetermined plane for recording a hologram of a diffusely reflecting object wherein the object is positioned to reflect light from said scene beam to the recording material; g. means for reflecting said reference beam onto said recording material; and h. a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pulse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.

Claim 20

A holographic apparatus having improved spatial coherence and uniform amplitude distribution comprising: a. a solid laserable material; b. means for pumping said laserable material into an excited stage; c. a resonant cavity enclosing said laserable material to cause the generation of a pulse of a substantially monochromatic, coherent light beam; d. a mode selector in said cavity for permitting a light pulse of substantially a single frequency to be built up, while providing substantially no transverse mode selection; e. optical means for splitting said light beam into a scene beam and a reference beam; f. a recording material disposed in a predetermined plane for recording a hologram of a diffusely reflecting object wherein the object is positioned to reflect light from said scene beam to the recording material; g. means for reflecting said reference beam onto said recording material; and h. a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pulse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.

Claim 21

A holographic apparatus having spatial coherence compensation and uniform amplitude distribution comprising: a solid state laser capable of generating a light beam pulse of substantially a single frequency, said laser including a longitudinal mode selecting means while providing substantially no transverse mode selection, whereby said light beam pulse contains a plurality of transverse modes; optical means for splitting said light beam into a scene beam and a reference beam; a recording material disposed in a predetermined plane to receive the reference beam for recording a hologram of a diffusely reflecting object, wherein the object is positioned to reflect light from said scene beam to the recording material; and a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pulse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.

Claim 22

A holographic apparatus having spatial coherence compensation and uniform amplitude distribution comprising: a solid state laser capable of generating a light beam pulse of substantially a single frequency, said laser including a longitudinal mode selecting means while providing substantially no transverse mode selection, whereby said light beam pulse contains a plurality of transverse modes; optical means for splitting said light beam into a scene beam and a reference beam; a recording material disposed in a predetermined plane to receive the reference beam for recording a hologram of a diffusely reflecting object, wherein the object is positioned to reflect light from said scene beam to the recording material; and a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pulse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.

Claim 23

Apparatus for constructing a hologram of a diffusely reflecting opaque object scene with a light source having poor spatial coherence, comprising: a laser light source having a light beam output with a plurality of transverse modes, means for directing a portion of the intensity of said laser light beam onto said diffusely reflecting object scene for reflection therefrom as an object modified beam, a hologram detector positioned in the path of said object modified beam, means for diverting another portion of the intensity of said laser light beam directly onto said detector as a reference beam for interference with the object modified beam, and means in the object beam between said laser and said object scene for diffusing said object beam so that substantially all illuminated points of the object scene are each illuminated by every transverse mode of said laser light output.

Claim 24

Apparatus for constructing a hologram of a diffusely reflecting opaque object scene with a light source having poor spatial coherence, comprising: a laser light source having a light beam output with a plurality of transverse modes, means for directing a portion of the intensity of said laser light beam onto said diffusely reflecting object scene for reflection therefrom as an object modified beam, a hologram detector positioned in the path of said object modified beam, means for diverting another portion of the intensity of said laser light beam directly onto said detector as a reference beam for interference with the object modified beam, and means in the object beam between said laser and said object scene for diffusing said object beam so that substantially all illuminated points of the object scene are each illuminated by every transverse mode of said laser light output.

Claim 25

Apparatus according to claim 17 wherein said laser light source includes a pulsed solid state laser.

Claim 26

A holographic apparatus having spatial coherence compensation and uniform amplitude distribution comprising: a solid state laser capable of generating a light beam pulse of substantially a single frequency, said laser inCluding substantially no transverse mode selection, whereby said light beam pulse contains a plurality of transverse modes; optical means for splitting said light beam into a scene beam and a reference beam; a recording material disposed in a predetermined plane to receive the reference beam for recording a hologram of a diffusely reflecting object, wherein the object is positioned to reflect light from said scene beam to the recording material; and a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pluse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.

Claim 27

A holographic apparatus having spatial coherence compensation and uniform amplitude distribution comprising: a solid state laser capable of generating a light beam pulse of substantially a single frequency, said laser inCluding substantially no transverse mode selection, whereby said light beam pulse contains a plurality of transverse modes; optical means for splitting said light beam into a scene beam and a reference beam; a recording material disposed in a predetermined plane to receive the reference beam for recording a hologram of a diffusely reflecting object, wherein the object is positioned to reflect light from said scene beam to the recording material; and a light diffuser interposed into the path of said scene beam for diffusing the scene beam in a manner to illuminate all the lighted portions of the object with radiation of all transverse modes present in said light beam pluse, whereby the object in the path of said scene beam reflects and diffuses said scene beam onto said recording material, said object operating as an additional light diffuser.