Abstract: Polarization based interferometric methods suffer from errors caused by the internal instrument birefringence. Disclosed herein are methods for using dual interferometric measurements allow separating the influence of instrument errors (e.g., due to geometry and birefringence errors) and the measured part. The interferometric system error in an interferometry system having two light sources orthogonally polarized with respect to each other wherein each light source reflects from a reference surface and a test surface, creating four reflected beams (Wr, Vr, Wt, Vt), may be determined by performing a first interference measurement (M1) from Wr-Vt. A second interference measurement (M2) from Wt-Vr is performed and a third measurement (M3), indicative of the interferometric system error, is calculated by averaging the first and second measurements ([M1+M2]/2).

Abstract: A source module (12) generates mutually orthogonally polarized beams of light as emanating from two spatially separated point sources (Sv, Sw) for use in a phase shifting interferometer.

Abstract: A source module (12) generates mutually orthogonally polarized beams of light as emanating from two spatially separated point sources (Sv, Sw) for use in a phase shifting interferometer.

Abstract: A back-end assembly for use with a front-end assembly in acquiring phase-shifted interferograms having a plurality of imaging modules (Ma, Mb, Mc). Each module (Ma, Mb, Mc) has a quarter wave plate (30a, 30b, 30c), a polarizer (32a, 32b, 32c), and an image sensor (34a, 34b, 34c) so that each polarizer has a different rotation orientation thus acquiring phase-shifted interferograms.

Abstract: A far-field measurement instrument has multiple imaging lenses cut into a pentagon shape and arranged in geodesic spherical configuration with a common field of view focused on the source of the scattered light to be measured. Aspheric lenses are used to facilitate collimation of large incident angles of scattered light. A measurement module, such as a camera, is used behind each lens. The measurement module may consist of an interferometer or Shack-Hartman wavefront sensor, thereby enabling the measurement of both intensity and phase of the scattered light.

Abstract: A far-field measurement instrument has multiple imaging lenses cut into a pentagon shape and arranged in geodesic spherical configuration with a common field of view focused on the source of the scattered light to be measured. Aspheric lenses are used to facilitate collimation of large incident angles of scattered light.

Abstract: A portable scatterometer and/or an angular radiated light measurement instrument that uses a measurement head which includes a double tapered fiber optic bundle with a concave front face to simultaneously collect partial or full hemispherically scattered light reflected from a point on a surface illuminated by a depolarized, telescopically focused, laser diode source, the light rays being received by each fiber normal to its face. The image of the collected light beams is minifled and coupled by the fiber optic bundle into an anti-blooming CID camera with an x-y scanning area array which converts the light beams to electrical signals. In a unique real time, 486-computer-controlled, data acquisition and reconstruction process, a frame grabber and a unique algorithm are used to collect over 200,000 points of light, reconstruct the data into a 2D or 3D scatter profile, and display the results, all within one second.

Abstract: A portable scatterometer and/or an angular radiated light measurement instrument that uses a measurement head which includes a double tapered fiber optic bundle with a concave front face to simultaneously collect partial or full hemispherically scattered light reflected from a point on a surface illuminated by a depolarized, telescopically focused, laser diode source, the light rays being received by each fiber normal to its face. The image of the collected light beams is minified and coupled by the fiber optic bundle into an anti-blooming CID camera with an x-y scanning area array which converts the light beams to electrical signals. In a unique real time, computer-controlled data acquisition and reconstruction process, a frame grabber and a unique algorithm are used to collect over 200,000 points of light, reconstruct the data into a 2D or 3D scatter profile and display the results, all within one second.

Abstract: A portable scatterometer and/or an angular radiated light measurement instrument that uses a measurement head which includes a double tapered fiber optic bundle with a concave front face to simultaneously collect partial or full hemispherically scattered light reflected from a point on a surface illuminated by a depolarized, telescopically focused, laser diode source, the light rays being received by each fiber normal to its face. The image of the collected light beams is minified and coupled by the fiber optic bundle into an anti-blooming CID camera with an x-y scanning area array which converts the light beams to electrical signals. In a unique real time, computer-controlled, data acquisition and reconstruction process, a frame grabber and a unique algorithm are used to collect over 200,000 points of light, reconstruct the data into a 2D or 3D scatter profile and display the results, all within one second.