A detector that detects relative positions of a first object and a second object in directions different from each other on a predetermined plane, includes an illumination optical system configured to illuminate a first mark provided on the first object and a second mark provided on the second object, and a detection optical system configured to detect interference light of diffracted lights from the first mark and the second mark illuminated by the illumination optical system. A light intensity distribution is formed, on a pupil plane of the illumination optical system, to illuminate the first mark and the second mark from a direction tilted with respect to a normal of the predetermined plane. A pupil plane of the detection optical system allows the interference light to pass through and block at least a part light other than the interference light.

The interferometer 10 according to this disclosure includes: a first optical component 12 that splits each of the P polarization component and the S polarization component of the light to be measured into the first optical path R1 and the second optical path R2 and combines the light to be measured; a second optical component 13 placed in the first optical path; a third optical component 14 that splits the light to be measured into the P polarization component and the S polarization component; and a P polarization detector 11a and an S polarization detector 11b that respectively detect the P polarization component and the S polarization component split by the third optical component, wherein the second optical component has an optical surface that changes the propagation direction of the light to be measured and gives a phase difference between the P polarization component and the S polarization component.

The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

A polarization holographic microscope system is disclosed. The polarization holographic microscope system can acquire a birefringence image and a three-dimensional phase image with high sensitivity by aperture synthesis of sample beams at various angles, and a sample image acquisition method using the microscope system.

A method and a device for characterizing the surface shape of an optical element. In the method, in at least one interferogram measurement carried out by an interferometric test arrangement, a test wave reflected at the optical element is caused to be superimposed with a reference wave not reflected at the optical element. In this case, the figure of the optical element is determined on the basis of at least two interferogram measurements using electromagnetic radiation having in each case linear input polarization or in each case circular input polarization, wherein the input polarizations for the two interferogram measurements differ from one another.

Systems or apparatuses may include a spatial modulator for spatially modulating light to produce spatially modulated light, a dispersing element for dispersing the modulated light to produce spatially modulated and dispersed light, a polarization-sensitive displacement element for providing a polarization dependent displacement of the dispersed light, and a detector for detecting the spatially modulated, dispersed and displaced light. The system and/or apparatus may include a broadband light source for providing broadband light, a linear polarizer for polarizing the broadband light, a double path interferometer including a sample path via the object and a reference path, a beam splitter for superposing a portion of the light from the sample path and a portion of the light from the reference path to create superposed light for spatial modulation, and/or a processor for processing an output of the detector to produce a three-dimensional image of the object.

A method of determining a displacement comprises: generating an interferometric superoscillatory field from coherent electromagnetic radiation, the interferometric superoscillatory field comprising an interference pattern between a reference field and a superoscillatory field; detecting with a detector a first set of intensity distributions of the interferometric superoscillatory field, each intensity distribution from a different polarisation state of the electromagnetic radiation; detecting with the detector a second set of intensity distributions of the interferometric superoscillatory field, each intensity distribution from the same polarisation states of the electromagnetic radiation as the first set of intensity distributions; extracting a first local wavevector distribution from the first set of intensity distributions and a second local wavevector distribution from the second set of intensity distributions; comparing the first local wavevector distribution and the second local wavevector distribution to identify any change in position of one or more features in the local wavevector distributions; and ascertaining that a lateral displacement has occurred between the interferometric superoscillatory field and the detector if a change in position is identified.

An interferometric measurement system includes ports configured to receive an optical signal from an optical source and an optical signal from a target. A photonic integrated circuit includes a variable delay configured to select between at least two optical paths from the input to an output such that the optical signal from the optical source passes to the output while experiencing an optical delay based on a selected one of the at least two optical paths where a loss of the optical signal from the optical source provided to the input that passes to the output is nominally the same for each of the at least two optical paths. An optical receiver is configured to receive the optical signal from the target and to receive the optical signal from the optical source that experiences the optical delay based on the selected one of the at least two optical paths and generates a corresponding electrical receive signal at an electrical output. A processor is configured to generate an interferometric measurement signal based on the receive signal.

An optical refraction barometer measures pressure based on refractivity changes and includes: an optical light source; an optical frequency controller; a first optical phase controller; a first polarization controller; an electronic reference arm in optical communication with the first polarization controller; a second optical phase controller in optical communication with the optical frequency controller; a second polarization controller in optical communication with the second optical phase controller; an electronic sample arm in optical communication with the second polarization controller and in electrical communication with the second optical phase controller; a second sideband frequency generator; a mixer in electrical communication with the detector and the second sideband frequency generator; and a first sideband frequency generator in electrical communication with the mixer; and a dual fixed length optical cavity refractometer.

An interferometer having a fundamental beam generator, a first second harmonic generator, a waveplate, a second second harmonic generator, a harmonic separator, and a polarizing beam splitter, mounted uniaxially, (i.e., the components are aligned along one optical axis), wherein the interferometer is adapted to change a diameter of a beam to match a diameter of a sample, and to change the diameter of the beam back to its original diameter.