An apparatus for and method of sensing alignment marks in which a self-referencing interferometer based sensor outputs standing images of the alignment marks and camera device is used to capture the images as output by the sensor and a detector is used to obtain phase information about the alignment marks from the images as output by the sensor.

A method for evaluating the quality of the measurement of an optical wavefront, said measurement being obtained by means of a wavefront analyzer by direct measurement, the method comprising: the acquisition (10) of an optoelectronic signal for the measurement of the wavefront by means of a wavefront sensor, said sensor comprising a two-dimensional detector; the determination (11) on the basis of said optoelectronic signal of at least one parameter characteristic of a parasitic component of the optoelectronic signal; the evaluation (12) of a quality factor of the measurement of the wavefront as a function of said at least one parameter characteristic of the parasitic component of the signal; the display (13) to a user of a level of quality of the measurement as a function of said quality factor.

A method for evaluating the quality of the measurement of an optical wavefront, said measurement being obtained by means of a wavefront analyzer by direct measurement, the method comprising: the acquisition (10) of an optoelectronic signal for the measurement of the wavefront by means of a wavefront sensor, said sensor comprising a two-dimensional detector; the determination (11) on the basis of said optoelectronic signal of at least one parameter characteristic of a parasitic component of the optoelectronic signal; the evaluation (12) of a quality factor of the measurement of the wavefront as a function of said at least one parameter characteristic of the parasitic component of the signal; the display (13) to a user of a level of quality of the measurement as a function of said quality factor.

An apparatus for and method of sensing alignment marks in which a self-referencing interferometer based sensor outputs standing images of the alignment marks and camera device is used to capture the images as output by the sensor and a detector is used to obtain phase information about the alignment marks from the images as output by the sensor.

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.

Provided herein are various enhancements for processing interference fringe data produced by optical interferometry and producing images from such interference fringe data. One example implementation includes a method comprising producing an interference fringe image by interfering multispectral optical signals of a scene supplied by optical collection devices. The method includes transforming the interference fringe image into a frequency domain representation comprising spectral channels corresponding to interfered combinations among the multispectral optical signals, determining pathlength errors of beam paths associated with the optical collection devices by concurrently processing the spectral channels of the frequency domain representation, and removing the pathlength errors in the frequency domain representation to produce a corrected frequency domain representation. The method also includes constructing a corrected image of the scene from visibility samples arising from the corrected frequency domain representation.

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.