US 3,957,353 A · Multiemulsion transparency providing separate phase and amplitude control

Abstract

Method and apparatus for making a hologram that controls both the amplitude and the phase of a reconstructing beam of light at each point on the surface of the hologram. The hologram is a transparency made from a conventional, color reversal photographic film that has multiple emulsion layers that are each selectively photosensitive to light of different wavelengths. The desired image to be produced from the hologram is initially processed into a matrix of Fourier transformed amplitude coefficients and a matrix of Fourier transformed phase coefficients. The hologram is made by first exposing the photographic film to an illumination pattern of the Fourier amplitude coefficients using light having a spectrum to which one of the emulsions is selectively photosensitive. The film is next exposed to an illumination pattern of the Fourier phase coefficients using light having a wavelength to which another emulsion of the film is selectively photosensitive. Two separate exposures are made on the film, and each exposure photographically records a separate set of Fourier transformed data describing the image to be produced. After the transparency is developed, the desired image is reconstructed by illuminating the transparency with a coherent beam of light. One emulsion layer on the film controls the amplitude transmittance according to the Fourier amplitude data and another emulsion layer controls the phase of the reconstructing beam of light passing through the transparency in accordance with the recorded Fourier phase data. A full color holographic image is obtainable by constructing three separate holograms, reconstructing each hologram with a different primary color and combining the three primary colors together to form one image.

Claims27

Dependent claims

A method of synthesizing a multiemulsion transparency for producing an image of an object with a constructing beam of light, comprising the steps of:

determining in matrix format the image of the object;
Fourier transforming the image matrix into two transmittance matrices, one matrix having amplitude transmittance elements and the other matrix having phase transmittance elements;
exposing a color reversal, multiemulsion photographic film to a representation of the amplitude elements with a first light having a spectrum to which only a first emulsion of the film is photosensitive;
exposing the film to a representation of the phase elements with a second light having a spectrum to which only a second emulsion of the film is photosensitive;
and processing the film into a transparency.

2 more elements

A multiemulsion transparancy for optically modulating a wave front by absorbing and phase shifting a beam of substantially monochromatic light passing therethrough, said modulation being describable by a complex transmittance function F(u,v)=A(u,v) exp[j.phi.(u,v)] that is a combination of an amplitude function A(u,v) and a phase function .phi.(u,v), comprising:

an amplitude transmittance controlling emulsion for attenuating the beam of substantially monochromatic light, the amplitude controlling emulsion having areas thereon of differing amplitude transmittance which correspond to the amplitude function A(u,v) and said emulsion exclusively attenuates the beam of light in accordance with said amplitude function;
and
an independent phase shifting emulsion attached thereto for slowing down the beam of light passing therethrough, the phase controlling emulsion having areas thereon of differing phase shift which correspond to the phase function .phi.(u,v) and the values of the phase shift in said phase controlling areas vary in a continuous manner over a range of 0 to 2.pi. radians of phase delay and the constructed wave front propagating on the axis of propagation of the light beam and said emulsion phase shifts the beam of light in accordance with said phase function.

A multiemulsion transparency for optically constructing an image by absorbing and phase shifting a beam of substantially monochromatic light passing therethrough, said constructed image being describable by a complex mathematical function f(x,y) that has Fourier transform F(u,v)=A(u,v) exp [j.phi.(u,v)] that is a combination of an amplitude function A(u,v) and a phase function .phi.(u,v), comprising:

an amplitude transmittance controlling emulsion for attenuating the beam of substantially monochromatic light, the amplitude controlling emulsion having areas thereon of differing amplitude transmittance which correspond to the amplitude function A(u,v) and said emulsion exclusively attenuates the beam of light in accordance with said amplitude function;
and
an independent phase shifting emulsion attached thereto for slowing down the beam of light passing therethrough, the phase controlling emulsion having areas thereon of differing phase shift which correspond to the phase function .phi.(u,v) and the values of the phase shift in said phase controlling areas vary in a continuous manner over a range of 0 to 2.pi. radius of phase delay and the constructed wave front propagating on the axis of propagation of the light beam and said emulsion phase shifts the beam of light in accordance with said phase function.

A multiemulsion transparency for optically constructing an image by absorbing and phase shifting a beam of substantially monochromatic light passing therethrough, said constructed image being describable by a complex mathematical function f(x,y) that has Fresnel transform F(u,v)=A(u,v) exp [j.phi.(u,v)] that is a combination of an amplitude function A(u,v) and a phase function .phi.(u,v), comprising:

an amplitude transmittance controlling emulsion for attenuating the beam of substantially monochromatic light, the amplitude controlling emulsion having areas thereon of differing amplitude transmittance which correspond to the amplitude function A(u,v) and said amulsion exclusively attenuates the beam of light in accordance with said amplitude function;
and
an independent phase shifting emulsion attached thereto for slowing down the beam of light passing therethrough, the phase controlling emulsion having areas thereon of differing phase shift which correspond to the phase function .phi.(u,v) and the values of the phase shift in said phase controlling areas vary in a continuous manner over a range of 0 to 2.pi. radius of phase delay and the constructed wave front propagating on the axis of propagation of the light beam and said emulsion phase shifts the beam of light in accordance with said phase function.

Dependencies are inferred from the claim text.

Multiemulsion transparency providing separate phase and amplitude control

Life of this patent

Multiemulsion transparency providing separate phase and amplitude control

Life of this patent

Abstract

Claims27