Apparatus for making annular holograms

Claim 2

Apparatus for recording a hologram comprising a wave-energy sensitive hologram plate disposed normal to a given axis, an object axially displaced from said plate and wholly confined within an interior region which is circularly symmetrical with respect to said given axis and which has a given maximum diameter, first means responsive to a first portion of coherent wave energy applied thereto for exposing at least a sector of an annular region of the surface of said hologram plate which annular region has a minimum diameter at least equal to said given maximum diameter with an information component of coherent wave-energy which has been spatially modulated by said object in response to illumination thereof by said first portion, and second means responsive to a second portion of said coherent wave energy applied thereto for simultaneously exposing at least said sector of said annular region with an annular reference beam component of coherent wave-energy from said second portion which is confined to an annular exterior region which is circularly symmetrical with respect to said given axis and which is distinct from but surrounds said interior region, whereby a hologram is formed by the interference between said information component and said reference beam component which is confined to said annular region of the surface of said hologram plate, wherein said object is a transparency lying in a plane normal to said given axis with said transparency being symmetrically disposed about said given axis, (The apparatus defined in claim 6,) further including an annular prism having an internal diameter greater than the external diameter of said annular region on said hologram plate, said prism being symmetrically disposed with respect to said given axis in normal relationship therewith, said prism being axially spaced from said transparency on the other side thereof from said hologram plate by a given distance, the refraction provided by said prism and said given distance being such that a beam of coherent light passing through said prism is directed through said transparency and then impinges solely on said annular region of said hologram plate.

Claim 3

Apparatus for recording a hologram comprising a wave-energy sensitive hologram plate disposed normal to a given axis, an object axially displaced from said plate and wholly confined within an interior region which is circularly symmetrical with respect to said given axis and which has a given maximum diameter, first means responsive to a first portion of coherent wave-energy applied thereto for exposing at least a sector of an annular region of the surface of said hologram plate which annular region has a minimum diameter at least equal to said given maximum diameter with an information component of coherent wave-energy which has been spatially modulated by said object in response to illumination thereof by said first portion, and second means responsive to a second portion of said coherent wave-energy applied thereto for simultaneously exposing at least said sectoR of said annular region with an annular reference beam component of coherent wave-energy from said second portion which is confined to an annular exterior region which is circularly symmetrical with respect to said given axis and which is distinct from but surrounds said interior region, whereby a hologram is formed by the interference between said information component and said reference beam component which is confined to said annular region of the surface of said hologram plate, wherein said second means includes means for supplying a converging wave annular reference beam component having a predetermined degree of convergence.

Claim 4

Apparatus for recording a hologram comprising a wave-energy sensitive hologram plate disposed normal to a given axis, an object axially displaced from said plate and wholly confined within an interior region which is circularly symmetrical with respect to said given axis and which has a given maximum diameter, first means responsive to a first portion of coherent wave-energy applied thereto for exposing at least a sector of an annular region of the surface of said hologram plate which annular region has a minimum diameter at least equal to said given maximum diameter with an information component of coherent wave-energy which has been spatially modulated by said object in response to illumination thereof by said first portion, and second means responsive to a second portion of said coherent wave-energy applied thereto for simultaneously exposing at least said sectoR of said annular region with an annular reference beam component of coherent wave-energy from said second portion which is confined to an annular exterior region which is circularly symmetrical with respect to said given axis and which is distinct from but surrounds said interior region, whereby a hologram is formed by the interference between said information component and said reference beam component which is confined to said annular region of the surface of said hologram plate, wherein said second means includes means for supplying a converging wave annular reference beam component having a predetermined degree of convergence.

Claim 5

Apparatus for recording a hologram comprising a wave-energy sensitive hologram plate disposed normal to a given axis, an object axially displaced from said plate and wholly confined within an interior region which is circularly symmetrical with respect to said given axis and which has a given maximum diameter, first means responsive to a first portion of coherent wave-energy applied thereto for exposing at least a sector of an annular region of the surface of said hologram plate which annular region has a minimum diameter at least equal to said given maximum diameter with an information component of coherent wave-energy which has been spatially modulated by said object in response to illumination thereof by said first portion, and second means responsive to a second portion of said coherent wave energy applied thereto for simultaneously exposing at least said sector of said annular region with an annular reference beam component of coherent wave-energy from said second portion which is confined to an annular exterior region which is circularly symmetrical with respect to said given axis and which is distinct from but surrounds said interior region, whereby a hologram is formed by the interference between said information component and said reference beam component which is confined to said annular region of the surface of said hologram plate, wherein said second means includes means for supplying a plane wave annular reference beam component, wherein said second means includes beam-enlarging collimating means symmetrically disposed about said given axis and responsive to a narrow axial beam of coherent light for producing an axial output beam of plane wave light having a diameter equal to the external diameter of said annular region, and means including said object for preventing a central portion of said output beam having said given maximum diameter from contributing to said annular reference beam component, further including beam-splitting means in the path of said narrow axial beam for splitting said narrow beam into an axial first component having a first intensity which is applied to said beam-enlarging collimating means and a nonaxial second component having a second intensity having a predetermined ratio with respect to the intensity of said first component, and means for illuminating said object with second component.

Claim 6

Apparatus for recording a hologram comprising a wave-energy sensitive hologram plate disposed normal to a given axis, an object axially displaced from said plate and wholly confined within an interior region which is circularly symmetrical with respect to said given axis and which has a given maximum diameter, first means responsive to a first portion of coherent wave-energy applied thereto for exposing at least a sector of an annular region of the surface of said hologram plate which annular region has a minimum diameter at least equal to said given maximum diameter with an information component of coherent wave-energy which has been spatially modulated by said object in response to illumination thereof by said first portion, and second means responsive to a second portion of said coherent wave energy applied thereto for simultaneously exposing at least said sector of said annular region with an annular reference beam component of coherent wave-energy from said second portion which is confined to an annular exterior region which is circularly symmetrical with respect to said given axis and which is distinct from but surrounds said interior region, whereby a hologram is formed by the interference between said information component and said reference beam component which is confined to said annular region of the surface of said hologram plate, wherein said second means includes means for supplying a plane wave annular reference beam component, wherein said second means includes beam-enlarging collimating means symmetrically disposed about said given axis and responsive to a narrow axial beam of coherent light for producing an axial output beam of plane wave light having a diameter equal to the external diameter of said annular region, and means including said object for preventing a central portion of said output beam having said given maximum diameter from contributing to said annular reference beam component, further including beam-splitting means in the path of said narrow axial beam for splitting said narrow beam into an axial first component having a first intensity which is applied to said beam-enlarging collimating means and a nonaxial second component having a second intensity having a predetermined ratio with respect to the intensity of said first component, and means for illuminating said object with second component.