Compensation for effects of mismatch in indices of refraction at a substrate-medium interface in non-confocal, confocal, and interferometric confocal microscopy

A confocal interferometry system for making interferometric measurements of locations within an object that is in a medium, there being a mismatch between indices of refraction of said object and said medium, said system comprising:

• a plate defining a pinhole positioned to receive a source beam and separate the source beam into a reference beam on one side of the pinhole and a measurement beam on the other side of the pinhole;
• an imaging system for imaging the pinhole onto a spot in the object so that the measurement beam is directed to said spot and produces for said spot a return measurement beam, said first imaging system also arranged to image said spot onto the pinhole so that the return measurement beam from said spot is directed back to said pinhole, wherein the pinhole combines the return measurement and reference beams to produce a combined beam;
• and
• a detector system including a detector element that receives the combined beam,
• wherein the return measurement beam travels along a corresponding path from the object to the detector system and wherein said interferometer includes a compensating layer of material positioned in the corresponding path of the return measurement beam, said compensating layer producing a mismatch in the index of refraction along the corresponding path of the return measurement beam that compensates for the mismatch between the indices of refraction of said object and said medium.

A confocal interferometry system for making interferometric measurements of locations within an object that is in a medium, there being a mismatch between indices of refraction of said object and said medium, said system comprising:

• an array of pinholes positioned to receive a source beam and, for each pinhole in the array of pinholes, separate the source beam into a corresponding reference beam on one side of the array of pinholes and a corresponding measurement beam on the other side of the array of pinholes;
• an imaging system arranged to image the array of pinholes onto an array of spots in the object so that the corresponding measurement beam for each pinhole of the array of pinholes is directed to a different corresponding spot of the array of spots and produces for that spot a corresponding return measurement beam, said first imaging system also arranged to image the array of spots onto the array of pinholes so that the corresponding return measurement beam from each spot of the array of spots is directed back to a corresponding different pinhole in the array of pinholes, wherein for each pinhole the pinhole array combines the return measurement and reference beams for that pinhole to produce a corresponding combined beam;
• and
• a detector system including an array of detector elements aligned with the array of pinholes so that the corresponding combined beam for each pinhole is directed to different corresponding detector element of the array of detector elements,
• wherein the return measurement beams travel along corresponding paths from the object to the detector system and wherein said interferometer includes a compensating layer of material positioned in the corresponding paths of the return measurement beams, said compensating layer producing a mismatch in the index of refraction along the corresponding paths of the return measurement beams that compensates for the mismatch between the indices of refraction of said object and said medium.

A microscope for making measurements of locations within an object that is in a medium, there being a mismatch in indices of refraction between said object and said medium, said microscope comprising:

• a source for generating an input beam;
• a detector system;
• an imaging system for focusing at least part of the input beam onto a selected spot in the object to produce a return beam;
• and
• an imaging system for imaging the selected spot onto the detector system,
• wherein the return beam travels along a path from the object to the detector assembly and wherein the second-mentioned imaging system includes a compensating layer of material positioned in the path of the return beam, said compensating layer producing a mismatch in the index of refraction along the path of the return beam that compensates for the mismatch in the indices of refraction of said object and said medium.