Longitudinal differential interferometric confocal microscopy

A differential interferometric confocal microscope for measuring an object, said microscope comprising:

• a source-side pinhole array;
• a detector-side pinhole array;
• and
• an interferometer that images each pinhole of the source-side pinhole array onto a corresponding different pair of two locations, one of which lies in a first object plane and the other of which lies in a second object plane that is parallel to and displaced from the first object plane, thereby generating a first image of the source-side pinhole array in the first object plane and a second image of the source-side pinhole array in the second object plane, said interferometer also projecting a first array of return measurement beams from the first image and a second array of return measurement beams from the second image toward the detector-side pinhole array to produce a first array of converging beams and a second array of converging beams, wherein the detector-side pinhole array generates an array of conjugated quadratures of fields that is a difference of conjugated quadratures of fields of the first and second arrays of converging beams.

A differential interferometric confocal microscope for measuring an object and which has, in the vicinity of where the object being measured is to be located, a first object plane and a second object plane that is displaced from and parallel to the first object plane, said microscope comprising:

• a source-side pinhole array;
• a detector-side pinhole array;
• and
• an interferometer that receives a beam from a selected pinhole of the source-side pinhole array and converges a first part of that received beam onto a corresponding first location in the first object plane and a second part of that received beam onto a corresponding second location in the second object plane, said interferometer also arranged to receive a first return beam from the first location and a second return beam from the second location and converge at least a part of each of the first and second return beams onto a corresponding pinhole of the detector-side pinhole array to produce a difference of conjugated quadratures of fields of the first and second return beams converging on that corresponding pinhole,
• wherein said selected pinhole is any pinhole of the source-side pinhole array.

A differential interferometric confocal microscope for measuring an object, said microscope comprising:

• a source-side pinhole array for producing an array of input beams;
• a detector-side pinhole array;
• and
• an interferometer including:
• a first optical element providing a first reflecting surface;
• a second optical element providing a second reflecting surface;
• and
• a beam splitter positioned between the first and second optical elements,
• wherein the beam splitter produces from the array of input beams a first array of measurement beams and a second array of measurement beams,
• wherein the first reflecting surface participates in focusing the first array of measurement beams onto a first array of locations on a first object plane in object space and the second reflecting surface participates in focusing the second array of measurement beams onto a second array of locations on a second object plane in object space, said first and second object planes being parallel to and displaced from each other,
• wherein the first array of measurement beams generates a first array of return beams from the object and the second array of measurement beams generates a second array of return beams from the object,
• wherein the first reflecting element participates in producing from the first array of return beams a first array of converging beams that converge to a first array of spots on a first image plane and the second reflecting element participates in producing from the second array of return beams a second array of converging beams that converge onto a second array of spots on a second image plane, said first and second image planes being adjacent to and on opposite sides of the detector-side pinhole array, and
• wherein the detector-side pinhole array combines the first and second arrays of converging beams to form an array of output beams.