A cascaded interferometric system for Fourier domain optical coherence tomography (OCT) in which the output of one sub-system interferometer is directed through a second sub-system interferometer for performing the Fourier transform in hardware.

Provided is a cold atomic beam generation technology that causes a cold atomic beam to travel in a direction different from the traveling direction of a pushing laser beam. The pushing laser beam is used to generate a cold atomic beam from atoms trapped in a space. Next, the cold atomic beam is deflected by using a zero magnetic field line of a quadrupole magnetic field in a two-dimensional magneto-optical trap mechanism or by using a drift direction of a standing light wave in a moving molasses mechanism.

A laser interference device includes: a measurement mirror being movable in an X direction; a reference mirror disposed at a position different from a position of the measurement mirror in a Y direction; a beam splitter having a splitting surface that divides a laser beam into a measurement light and a reference light; a first light guide configured to guide the measurement light incident from the beam splitter and emit the measurement light toward the measurement mirror; and a second light guide configured to guide the reference light incident from the beam splitter and emit the reference light toward the reference mirror, in which a first distribution path formed by the first light guide and a second distribution path formed by the second light guide are mutually equal in a mechanical path length and an optical path length.

An optical system can include a mirror that reflects incoming light to a sensor for detection. The position and/or orientation of the mirror can be controlled to reflect incoming light from different locations and/or directions. Position and/or orientation of the mirror may be tracked and/or detected by an optical position sensor. The position sensor can transmit a beam to a reflector on the mirror, and the reflected beam can be received by the position sensor. Characteristics of the reflected beam can be measured to determine the position and/or orientation of the mirror. For example, the beam can be used for interferometric and/or intensity measurements, which can then be correlated with a position and/or orientation of the mirror.

A substrate holder for use with an interferometer comprises a first and second support each comprising a bearing land and a bearing base arranged to form a bearing pocket and a gas inlet fluidly coupled to the bearing pocket. The first support and the second support are positioned relative to one another such that the first bearing pocket is opposed to the second bearing pocket thereby forming a measurement cavity between the first support and the second support. At least one of the first support and the second support comprises reference optics through which one or more interferometric or optical measurements can be taken. Gas supplied to the first bearing pocket and gas supplied to the second bearing pocket form an air bearing in the measurement cavity for supporting a substrate in the measurement cavity without contact between the substrate, the first support, and the second support.

In some embodiments, systems, methods, and media for multiple reference arm spectral domain optical coherence tomography are provided which, in some embodiments, includes: a sample arm coupled to a light source; a first reference arm having a first path length; a second reference arm having a longer second path length; a first optical coupler that combines light from the sample arm and the first reference arm; a second coupler that combines light from the sample arm and the second reference arm; and an optical switch comprising: a first input port coupled to the first optical coupler; a second input coupled to the second coupler via an optical waveguide that induces a delay at least equal to an acquisition time of an image sensor; and an output coupled to the image sensor.

An electro-optical system has a laser drive electronic circuit, a laser light source and an optical interferometer, forming a closed loop. The laser drive electronic circuit is arranged to receive a reference frequency as input, and a beat frequency as feedback. The laser drive electronic circuit generates a drive output based on a phase difference between the reference frequency and the beat frequency. The optical interferometer, coupled to the laser light, generates optical energy at the beat frequency.

A reflectometer or ellipsometer integrated with a processing tool includes a source module configured to generate a input beam, and a first mirror arranged to receive the input beam. The first mirror is configured to collimate the input beam and direct the input beam toward an aperture plate. The aperture plate has at least two apertures. One of the at least two apertures is arranged to define a measurement beam from a portion of the input beam, and one of the at least two apertures is arranged to define a reference beam from a portion of the input beam. An optical element is arranged within an optical path of the reference beam and outside an optical path of the measurement beam. The optical element is configured to direct the reference beam toward a third mirror. A second mirror is arranged to receive the measurement beam and focus the measurement beam through a window and onto a surface of a sample. The window forms part of a chamber of the processing tool and the sample is disposed within the chamber. At least a portion of the measurement beam is reflected from the surface of the sample as a reflected beam. The second mirror is arranged to receive the reflected beam and direct the reflected beam toward the optical element. The optical element is configured to direct the reflected beam toward the third mirror. The third mirror is arranged to receive the reference beam and the reflected beam and focus the reference beam and the reflected beam onto a collection plane.

A light emitting device, an optical detection system, an optical detection device and an optical detection method, the light emitting device comprising: a light source (01), and an aperture limiting unit (03) located on an emergent light path of the light source (01); the light source (01) is used to emit light; and the aperture limiting unit (03) is used to limit the aperture of light emitted by the light source (01) when a current detection area of an object to be tested (05) has a high aspect ratio structure so as to block a portion of light having a large included angle with the normal direction of the object to be tested (05), such that the light is incident on the current detection area of the object to be tested (05) along the normal direction of the object to be tested (05) or along a direction that forms a small angle with the normal direction of the object to be tested (05). Thus, the high aspect ratio structure of the current detection area may be effectively detected.

An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.