A method, an interferometer, and a signal processing device, each for determining an input phase and/or an input amplitude of an input light field, are disclosed. Here, an input light field is divided into a first light field and a second light field by amplitude splitting. The first light field and the second light field are propagated such that the propagated second light field is defocused relative to the propagated first light field. The propagated first light field is superimposed on the propagated light field and caused to interfere.

A displacement measurement device 10 is provided with: a laser light source 11 for emitting laser light to a measurement area R of a measurement target object S; a focusing optical system (the beam splitter 151, the first reflecting mirror 1521, the condenser lens 155) having a front focal point in the measurement area R and a rear focal point on a predetermined imaging surface (the detection surface 1561); a non-focusing optical system (the beam splitter 151, the diffuser 153, the second reflecting mirror 1522, and the condenser lens 155) in which light from a measurement area R of a correspondence point in the measurement area corresponding to each point of the imaging surface with respect to the focusing optical system is incident on the point of the imaging surface; and a photodetector (image sensor 156) configured to detect light intensity on the imaging surface for each point. Thus, corresponding to each of a large number of points in the measurement area R, main reflected light reflected at the point and reference light reflected at the surrounding range of the point are incident on each of a large number of points in the imaging surface, and the main reflected light and the reference light interfere at a large number of points in the imaging surface. Thus, an interference pattern is obtained.

The present invention is directed to the provision of an interferometer and a phase shift amount measuring apparatus that can precisely operate in the EUV region. The interferometer according to the invention comprises an illumination source for generating an illumination beam, an illumination system for projecting the illumination beam emitted from the illumination source onto a sample, and an imaging system for directing the reflected beam by the sample onto a detector. The illumination system includes a first diffraction grating for producing a first and second diffraction beams which respectively illuminate two areas on the sample where are shifted from each other by a given distance, and the imaging system includes a second grating for diffracting the first and second diffraction beams reflected by the sample to produce a third and fourth diffraction beams which are shifted from each other by a given distance.

Object interference in biological samples generated by lateral shearing interference microscopes is addressed by a shearing microscope slide comprising a periodic structure having alternating reference and sample regions. In some embodiments, the reference regions are configured to provide references that remove sample overlap in a sheared microscopic measurement. A system for generating sheared microscopic measurements is also provided that comprises an inlet configured to receive a sample material, an outlet configured to release a portion of the sample material, and a periodic structure having a plurality of interleaved reference and sample channels. In some cases, the sample channels are configured to accommodate a flow of sample material from the inlet to the outlet and the reference channels are configured to provide references that remove sample overlap in a sheared microscopic measurement.

An optical system includes a light source, a target device, an image detector, and an autocollimator that receives a beam of electromagnetic radiation from the light source, directs the beam to the target device, and directs the beam to the image detector. The autocollimator includes a first polarizing beam splitter that directs the beam to the target device and receives the beam reflected off of the target device, a second polarizing beam splitter that receives the beam from the first polarizing beam splitter, directs the beam to a diffraction grating device, returns diffracted electromagnetic radiation from the diffraction grating device to an array of detectors, and directs the diffractive electromagnetic radiation, a camera that measures an interference pattern of diffracted electromagnetic radiation from the second polarizing beam splitter and captures an image, and a lens assembly that focuses electromagnetic radiation from the target device to the diffraction grating device.

The optical angle sensor comprises a diffraction unit, a light source, a light receiving unit, and a plurality of reflection units. The diffraction unit includes a first diffraction part for generating combined light and a second diffraction part for diffracting a first light and a second light a plurality of times. The plurality of reflection units includes a first reflection unit, a second reflection unit, a third reflection unit that reflects the first light and the second light through the second diffraction part toward the second diffraction part, fourth reflection unit, and fifth reflection unit. The calculating unit, with the rotation of the diffraction unit, calculates the amount of change in the angle based on the change in the interference signal caused by the combined light generated on the light receiving surface.

A defect detection device 10 is provided with: a laser light source 11 for irradiating laser light to a measurement region R of a surface of an inspection object S; a laser light source control unit 15 for controlling the laser light source so as to cause laser light to be outputted continuously or quasi-continuously for a time longer than a period of vibration generated in the inspection object; an interferometer (speckle shearing interferometer 14) for generating interference light in which reflected light of the laser light reflected in the measurement region and reference laser light emitted from the laser light source 11 interfere; a detector (image sensor 145) for detecting the intensity of the interference light for each point in the measurement region R; a phase shifter 143 for shifting the phase of the reflected laser light or the reference laser light; an integrated intensity pattern determination unit 16 for obtaining an integrated intensity obtained by integrating the intensity for each point over an integration time longer the period of the vibration in three or more phases, the phase being shifted by the phase shifter 143 into three or more different phases; an interference degree distribution generation unit 17 for obtaining the distribution of the degree of interference based on the integrated intensity obtained in each of the three or more phases for each point; and a defect detection unit 18 for detecting a defect in the measurement region R based on the distribution of the degree of interference in the measurement region R.

Provided is an ellipsometer including a polarizing optical device configured to separate light, reflected from a sample that is irradiated with illumination light comprising a linearly polarized light, into a first linearly polarized light in a first polarization direction and a second linearly polarized light in a second polarization direction that is orthogonal to the first polarization direction, and a light-receiving optical system configured to calculate an Ψ and Δ, an amplitude ratio and a phase difference of the two polarized light respectively, from an interference fringe formed by interference between the first linearly polarized light and the second linearly polarized light after passing through an analyzing device with transmission axis different from the first polarization direction and the second polarization direction.

A method for high-accuracy wavefront measurement based on grating shearing interferometry, which adopts a grating shearing interferometer system comprising an illuminating system, an optical imaging system under test, an object plane diffraction grating plate, an image plane diffraction grating plate, a two-dimensional photoelectric sensor, and a calculation processing unit. The object plane diffraction grating plate and the image plane diffraction grating plate are respectively arranged on the object plane and the image plane of the optical imaging system under test. The shearing phase of 1.sup.st-order diffracted beam and −1.sup.st-order diffracted beam is exactly extracted through phase shifting method, and the original wavefront is obtained by carrying out reconstruction algorithm according to a shear ratio of 2s, such that the accuracy of wavefront measurement of the optical imaging system under test is improved, wherein s is the shear ratio of the grating shearing interferometer.

A method for high-accuracy wavefront measurement based on grating shearing interferometry, which adopts a grating shearing interferometer system comprising an illuminating system, an optical imaging system under test, an object plane diffraction grating plate, an image plane diffraction grating plate, a two-dimensional photoelectric sensor, and a calculation processing unit. The object plane diffraction grating plate and the image plane diffraction grating plate are respectively arranged on the object plane and the image plane of the optical imaging system under test. The shearing phase of 1.sup.st-order diffracted beam and −1.sup.st-order diffracted beam is exactly extracted through phase shifting method, and the original wavefront is obtained by carrying out reconstruction algorithm according to a shear ratio of 2s, such that the accuracy of wavefront measurement of the optical imaging system under test is improved, wherein s is the shear ratio of the grating shearing interferometer.