The present disclosure provides a dispersion measurement device and method based on a Franson second-order quantum interference technology. The device includes: an energy-time entangled twin-photon source configured to generate a plurality of optical signals, where the optical signals each include a signal photon and an idle photon; a polarization splitter configured to split the signal photon and the idle photon, and enable the signal photon to pass through a to-be-measured dispersive medium, such that a correlation time processing module records, under a width of a coincidence measurement integration window, first time of the idle photon arriving at a first single-photon detector, and second time of the signal photon arriving at a second single-photon detector, and obtains a twin-photon conference time width based on the first time and the second time; and a processing module.

A device for measuring point diffraction interferometric wavefront aberration having an optical source, an optical splitter, a first light intensity and polarization regulator, a phase shifter, a second light intensity and polarization regulator, an ideal wavefront generator, an object precision adjusting stage, a measured optical system, an image wavefront detection unit, an image precision adjusting stage, and a data processing unit. A method for detecting wavefront aberration of the optical system by using the device is also disclosed.

An apparatus and method for measuring amplitude and/or phase of a molecular vibration uses a polarization modulated pump beam and a stimulating Stokes beam on a probe of a scanning probe microscope to detect a Raman scattered Stokes beam from the sample. The detected Raman scattered Stokes beam is used to derive at least one of the amplitude and the phase of the molecular vibration.

A pair of light rays spatially-sheared with a controllable beam-shear distance is generated by a module having a beamsplitter (BS) and two mirrors. The BS splits an input light ray into first and second split light rays respectively propagated on first and second light paths. The two mirrors are respectively located at distal ends of the two light paths, and cause each split light ray to undergo a two-stage reflection, thereby generating first and second reflected light rays directed to the BS. The BS processes the two reflected light rays to generate the pair of spatially-sheared light rays. Orientations of the two mirrors in yaw angle, pitch angle, or both, are jointly adjustable to realize and control the beam-shear distance without using any birefringent crystal-based prism. The module is used to form differential interference contrast (DIC) microscopes providing variable shear distances, advantages of orientation independence, etc.

An optical frequency measurement system includes a beam splitter configured to split a light beam into a plurality of measurement beams, including a first measurement beam and a second measurement beam; a first optical frequency measurement subsystem configured to receive the first measurement beam and measure a first frequency of the first measurement beam with a first accuracy range to obtain a first measured frequency that corresponds to a frequency of the light beam; and a second optical frequency measurement subsystem configured to receive the second measurement beam and measure a second frequency of the second measurement beam with a second accuracy range that is narrower than the first accuracy range to obtain a second measured frequency that corresponds to the frequency of the light beam with a higher accuracy than the first measured frequency.

A tri-mask optical polarization diversity receiver with a single input terminal and three output terminals prevents polarization induced signal fade, and may be used in an optical interferometry system for coherent detection. The device is composed of optical collimators, non-polarizing beam splitters, linear polarizers and photodetectors. In addition, the structural design incorporates two mechanically identical modulets, as well as a beam displacement compensation mechanism for ease of alignment and assembly. Compared to fiber-based design, the free-space configuration gets rid of inevitable birefringence in fused fiber couplers which detrimentally alter the polarization state received by the polarizers. As a result, it facilitates effective and precise measurements of optical interference with optimized visibility.

Differential Holography technology measures the amplitude and/or phase of, e.g., an incident linearly polarized spatially coherent quasi-monochromatic optical field by optically computing the first derivative of the field and linearly mapping it to an irradiance signal detectable by an image sensor. This information recorded on the image sensor is then recovered by a simple algorithm. In some embodiments, an input field is split into two or more beams to independently compute the horizontal and vertical derivatives (using amplitude gradient filters in orthogonal orientations) for detection on one image sensor in separate regions of interest (ROIs) or on multiple image sensors. A third unfiltered beam recorded in a third ROI directly measures amplitude variations in the input field to numerically remove its contribution as noise before recovering the original wavefront using a numerical in algorithm. When combined, the measured amplitude and phase constitute a holographic recording of the incident optical field.

A phase difference measuring device is provided with a phase conversion device and a detection device. The phase conversion device converts a first laser beam that passes therethrough so that the first laser beam includes a phase distribution of one cycle in an azimuth direction in a cross section of the first laser beam included in an arbitrary virtual plane perpendicular to an optical axis of the first laser beam. The detection device detects an azimuth angle of an intensity centroid of an interference pattern generated by at least a part of a first laser beam that has passed through the phase conversion device, and a part of a second laser beam that derives from a laser beam as seed light from which the first laser beam derives, of which an optical intensity is same as the at least a part of the first laser beam, and detects an inter-beam phase difference of the second laser beam.

The present disclosure provides a dispersion measurement device and method based on a Franson second-order quantum interference technology. The device includes: an energy-time entangled twin-photon source configured to generate a plurality of optical signals, where the optical signals each include a signal photon and an idle photon; a polarization splitter configured to split the signal photon and the idle photon, and enable the signal photon to pass through a to-be-measured dispersive medium, such that a correlation time processing module records, under a width of a coincidence measurement integration window, first time of the idle photon arriving at a first single-photon detector, and second time of the signal photon arriving at a second single-photon detector, and obtains a twin-photon conference time width based on the first time and the second time; and a processing module.

A method includes generating a source beam of heterodyne light toward a test layer so that the source beam is incident on the test layer at a first incidence angle. The source beam is polarized, thereby forming a reference beam. A portion of the source beam that is reflected by the test layer is polarized, thereby forming a test beam. An intensity signal of the reference beam and an intensity signal of the test beam are measured. A difference between a phase of the intensity signal of the test beam and a phase of the intensity signal of the reference beam is determined. A refractive index, an extinction coefficient, and a thickness of the test layer are determined based on the difference between the phase of the intensity signal of the test beam and the phase of the intensity signal of the reference beam.