A surface shape detection device using differential interference optics achieves restoration error reduction of a surface shape while maintaining resolution. The surface shape detection device includes: a light spot scanning unit such as a wafer rotation direction drive unit that scans a wafer surface with a light spot; an interference light detection mechanism such as a differential interference optical system that detects interference light of light obtained by scanning a surface of an inspection target with a plurality of the light spots separated by a predetermined design distance; and a surface shape restoration processing unit such as a wafer surface shape restoration unit that samples, at a predetermined quantization time interval, and calculates information of the interference light, and performs restoration processing on a surface shape of the wafer, in which the predetermined design distance is larger than a quantization distance interval corresponding to the predetermined quantization time interval.

A resonator is provided that includes opposing mirrors arranged substantially parallel to each other and separated to confine reflections for gain. A gain medium is between the opposing mirrors. A pump pumps the gain medium. At least one microrefractive element, or tens, hundreds, thousands, millions or more, stabilizes the resonator. The refractive element is disposed between the opposing mirrors and is configured to support a laser beam at a position of the refractive element. A method for producing laser light directs pump light onto one or a plurality of microrefractive elements. Reflections from the one or a plurality of microrefractive elements are confined in a resonator volume. Gain is provided in the resonator volume. Laser energy is emitted from the resonator volume.

An optical measurement device includes: a frame measurement unit for measuring magnitude of deformation of an optical detection platform frame, and a correction module for correcting the position of a substrate carrier and/or the position of an optical detection unit according to the magnitude of deformation of the optical detection platform frame, so as to eliminate an error in measurement of mark positions due to deformation of the frame. An optical measurement method is also disclosed.

A position measurement system configured to measure a position of an object. The system includes an optical system to obtain a first measurement wave and a second measurement wave from a radiation source, and to allow the first and second measurement wave to at least partially interfere with each other after interaction of at least one of the first and second measurement wave with the object to form a first detection beam. The system further includes a first detector to receive the first detection beam. The system also has a processing unit configured to receive an output from the first detector and to determine a signal representative for the position of the object from the output, wherein the optical system includes a phase modulator configured to modulate a phase difference between the first measurement wave and the second measurement wave.

Apparatus and methods are described including a line spectrometer that receives a point of light. The line spectrometer includes a first optical element, and a second optical element configured to convert the point of light to a line of light and to direct the line of light toward the first optical element. The first optical element defines first and second surfaces, a distance between the first and second surface varying as a function of distance along the first optical element, the first optical element thereby being configured to generate first and second reflected lines of light that reflect respectively from the first and second surfaces. A detector array receives the first and second lines of light, and generates an interferogram in response thereto. A computer processor determines a spectrum of the point of light, by analyzing the interferogram. Other applications are also described.

An interferometry system including a coherent light source operable to generate a beam of coherent light is provided. Separate waveguide pathways are optically associated between the coherent light source a photodetector. A transceiving segment can also be optically associated with each waveguide pathway at a location between the coherent light source and the photodetector. Each transceiving segment can be configured to emit an emitted beam of coherent light and positioned to receive a received portion of an emitted beam of coherent light emitted from a transceiving segment optically associated with a different waveguide pathway. The received portion of the emitted beam of coherent light can be combined with coherent light from the waveguide pathway receiving the received portion of the emitted beam of coherent light to form an optical interference signal. Accordingly, each waveguide pathway can be further configured to direct a separate optical interference signal toward a respective photodetector.

A position measurement system includes an interferometer to determine a position of an object. The interferometer is arranged to generate a first, second and third signals representative of the position by irradiating respective first, second and third areas of a reflective surface of the object. Along a line, the first and second areas are at a first distance relative to each other, the second and third areas are at a second distance relative to each other, and the first and third areas are at a third distance relative to each other. The interferometer is arranged to provide a rotation signal representative of a rotation of the object along an axis based on the first, second and third signals. The axis is parallel to the reflective surface and perpendicular to the line.

A wear amount measuring apparatus includes a light source, a light transmission unit, a first and a second irradiation unit, a spectroscope and an analysis unit. The light transmission unit splits a low-coherence light from the light source into a first and a second low-coherence light. The first and the second irradiation units irradiate the first and the second low-coherence light to the component to receive reflected lights from the component. The light transmission unit transmits the reflected lights received by the first irradiation unit and the second irradiation unit to the spectroscope. The spectroscope configured to detect intensity distribution of the reflected lights from the first and the second irradiation unit. The analysis unit calculates a thickness difference between a thickness of the component at the first measuring point and that at the second measuring point by performing Fourier transform on the intensity distribution.

A position measurement system configured to measure a position of an object. The system includes an optical system to obtain a first measurement wave and a second measurement wave from a radiation source, and to allow the first and second measurement wave to at least partially interfere with each other after interaction of at least one of the first and second measurement wave with the object to form a first detection beam. The system further includes a first detector to receive the first detection beam. The system also has a processing unit configured to receive an output from the first detector and to determine a signal representative for the position of the object from the output, wherein the optical system includes a phase modulator configured to modulate a phase difference between the first measurement wave and the second measurement wave.

The present disclosure provides an optical coherence tomography (OCT) system for characterising first and second areas of interest of a material. The OCT system comprises first and second optical elements in use positioned at the first and second areas of interest of the material. The first and second optical elements are at least partially transmissive for electromagnetic radiation. The system further comprises first and second scanning heads in use positioned at the first and second optical elements, respectively, to receive electromagnetic radiation that has interacted with the material at the first and second areas of interest. In addition, the system comprises at least one detector optically coupled to the first and second scanning heads. The first and second optical elements are arranged such that respective reference radiation associated with the first and second optical elements is generated by reflection at interfaces of or at the first and second optical elements, respectively, and the first and second optical elements are arranged or positioned such that an optical path length difference between the reference radiation associated with the first optical element reference radiation and electromagnetic radiation that interacted with the material associated with the first optical element differs from an optical path length difference between the reference radiation associated with the second optical element and electromagnetic radiation that interacted with the material associated with the second optical element.