Phase gradient contrast microscope

Claim 1

A method for producing an intensity image of the component of the spatial derivative of optical phase retardation in a particular direction from a transparent phase object comprising the steps of: producing a beam of collimated coherent light; directing said beam of collimated coherent light through a transparent phase object substantially located on a plane; directing said beam of collimated coherent light, after it has passed through said transparent phase object, to real time photorefractive holographic means for producing and recording a hologram of said transparent phase object; incrementally shifting the position of said transparent phase object; directing said beam of collimated coherent light through said incrementally shifted transparent phase object; directing said beam of collimated coherent light, after it has passed through said incrementally shifted transparent phase object, to said real time photorefractive holographic means for generating a phase conjugate beam of said transparent phase object; directing said phase-conjugate beam of said transparent phase object through said shifted transparent phase object; directing said phase-conjugate beam of said transparent phase object, after it has passed through said shifted transparent phase object, to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object, but not in the plane of the object, sufficiently far back or forward for a viewer to obtain an intensity image of the component of the spatial derivative of optical phase retardation in a particular direction.

Claim 2

A method for producing an intensity image of the component of the spatial derivative of optical phase retardation in a particular direction from a transparent phase object comprising the steps of: producing a beam of collimated coherent light; directing said beam of collimated coherent light through a transparent phase object substantially located on a plane; directing said beam of collimated coherent light, after it has passed through said transparent phase object, to real time photorefractive holographic means for producing and recording a hologram of said transparent phase object; incrementally shifting the position of said transparent phase object; directing said beam of collimated coherent light through said incrementally shifted transparent phase object; directing said beam of collimated coherent light, after it has passed through said incrementally shifted transparent phase object, to said real time photorefractive holographic means for generating a phase conjugate beam of said transparent phase object; directing said phase-conjugate beam of said transparent phase object through said shifted transparent phase object; directing said phase-conjugate beam of said transparent phase object, after it has passed through said shifted transparent phase object, to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object, but not in the plane of the object, sufficiently far back or forward for a viewer to obtain an intensity image of the component of the spatial derivative of optical phase retardation in a particular direction.

Claim 5

A method for producing an intensity image from a transparent phase object comprising the steps of: generating a laser beam; expanding said laser beam by means of a beam expander; opening a shutter disposed in the path of said expanded laser beam; splitting said expanded laser beam into first and second beams, after said expanded laser beam passes through said shutter, by means of a beam splitter; directing said first beam through a transparent phase object substantially located on a plane; focusing said first beam, after said first beam passes through said transparent phase object, into a photorefractive hologram recording crystal that records a hologram after a certain write time has elapsed, by means of a lens; closing said shutter once said write time expires; shifting the position of said transparent phase object an incremental amount; opening said shutter, for a time short compared to said write time, so that said first beam from said beam splitter is directed through said shifted transparent phase object, and through said lens into said photorefractive hologram recording crystal, such that a phase conjugate beam of said transparent phase object is produced traveling in the opposite direction of said first beam; collimating said phase-conjugate beam of said transparent phase object by means of said lens; directing said collimated phase-conjugate beam of said transparent phase object through said shifted transparent phase object; splitting said collimated phase-conjugate beam into third and fourth beams, after said collimated phase-conjugate beam of said transparent phase object passes through said shifted transparent phase object, by means of said beam splitter: directing said third beam to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object, but not in the plane of the object, sufficiently far back or forward for a viewer to obtain a gradient intensity image of said transparent phase object.

Claim 6

A method for producing an intensity image from a transparent phase object comprising the steps of: generating a laser beam; expanding said laser beam by means of a beam expander; opening a shutter disposed in the path of said expanded laser beam; splitting said expanded laser beam into first and second beams, after said expanded laser beam passes through said shutter, by means of a beam splitter; directing said first beam through a transparent phase object substantially located on a plane; focusing said first beam, after said first beam passes through said transparent phase object, into a photorefractive hologram recording crystal that records a hologram after a certain write time has elapsed, by means of a lens; closing said shutter once said write time expires; shifting the position of said transparent phase object an incremental amount; opening said shutter, for a time short compared to said write time, so that said first beam from said beam splitter is directed through said shifted transparent phase object, and through said lens into said photorefractive hologram recording crystal, such that a phase conjugate beam of said transparent phase object is produced traveling in the opposite direction of said first beam; collimating said phase-conjugate beam of said transparent phase object by means of said lens; directing said collimated phase-conjugate beam of said transparent phase object through said shifted transparent phase object; splitting said collimated phase-conjugate beam into third and fourth beams, after said collimated phase-conjugate beam of said transparent phase object passes through said shifted transparent phase object, by means of said beam splitter: directing said third beam to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object, but not in the plane of the object, sufficiently far back or forward for a viewer to obtain a gradient intensity image of said transparent phase object.

Claim 9

A method for producing an intensity image from a transparent phase object comprising the steps of: generating a laser beam; expanding said laser beam by means of a beam expander; splitting said expanded laser beam into first and second beams; directing said first beam through a transparent phase object substantially located on a plane; focusing said first beam, after said first beam passes through said transparent phase object, into a photorefractive hologram recording crystal such that a phase-conjugate beam of said transparent phase object traveling in the opposite direction of said first beam is produced; collimating said phase-conjugate beam of said transparent phase object by means of said lens; directing said collimated phase-conjugate beam of said transparent phase object through said transparent phase object; shifting the position said transparent phase object; splitting said collimated phase-conjugate beam into third and fourth beams, after said collimated phase-conjugate beam of said transparent phase object passes through said shifted transparent phase object, by means of said beam spliter; directing said third beam to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object but not in the plane of the object, sufficiently far back or forward for a viewer to obtain a gradient intensity image of said transparent phase object.

Claim 10

A method for producing an intensity image from a transparent phase object comprising the steps of: generating a laser beam; expanding said laser beam by means of a beam expander; splitting said expanded laser beam into first and second beams; directing said first beam through a transparent phase object substantially located on a plane; focusing said first beam, after said first beam passes through said transparent phase object, into a photorefractive hologram recording crystal such that a phase-conjugate beam of said transparent phase object traveling in the opposite direction of said first beam is produced; collimating said phase-conjugate beam of said transparent phase object by means of said lens; directing said collimated phase-conjugate beam of said transparent phase object through said transparent phase object; shifting the position said transparent phase object; splitting said collimated phase-conjugate beam into third and fourth beams, after said collimated phase-conjugate beam of said transparent phase object passes through said shifted transparent phase object, by means of said beam spliter; directing said third beam to observing means; and positioning said observing means back or forward from said plane, close to the transparent phase object but not in the plane of the object, sufficiently far back or forward for a viewer to obtain a gradient intensity image of said transparent phase object.