According to one embodiment, a three-dimensional (3D) measuring device is provided. The 3D measuring device includes a processor system that is configured to generate a point cloud representing multiple surfaces. The point cloud includes multiple scan points. Generating the point cloud includes receiving spherical coordinates for a scan point, the spherical coordinates comprising a distance (r), a polar angle (θ), and an azimuth angle (φ). Generating the point cloud further includes homogenizing a scan point density of the surfaces by filtering the scan points. The homogenizing includes computing a value (p) for the scan point based on the spherical coordinates. Based on the value exceeding a predetermined threshold, storing the scan point as part of the point cloud, and based on the value not exceeding the predetermined threshold, discarding the scan point.

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.

An interferometer system comprises a sample interferometer arm for guiding a first wave to a sample, and receiving a reflected wave from the sample and a phase amplifier for amplifying a phase shift of the reflected wave, to provide phase-shift-amplified intermediate wave. The interferometer system can also comprise an additional interferometer arm for guiding an additional wave to combine with the intermediate wave, to provide an output wave, and a detector for detecting the output wave.

Reference and test waves are directed in a common path mode in a fiber tip diffraction interferometer. A first fiber can be used to generate the reference wave and a second fiber can be used to generate the test wave. Each fiber can include a single mode fiber tip that defines a wedge at an end without a coating on end surface or a tapered fiber tip. The fiber tip diffraction interferometer can include an aplanatic pupil imaging lens or system disposed to receive both the test wave and the reference wave and a sensor configured to receive both the test wave and the reference wave.

A single-laser light source system for cold atom interferometers, comprising: a reference light module including a narrow-bandwidth laser and a frequency stabilization module and an optical frequency shift module including a first electro-optic modulator and a first narrow-bandwidth optical-fiber filter. The first electro-optic modulator is connected to the first narrow-bandwidth optical-fiber filter by an optical fiber, and the first electro-optic modulator is connected to the laser by an optical fiber. The first electro-optic modulator receives an initial light from the laser, modulates the initial light by a modulation signal with a preset frequency, and generates sidebands with the preset frequency. The first narrow-bandwidth optical-fiber filter filters the optical signal at the output of the first electro-optic modulator to obtain a frequency-shifted light as the +1-order sideband. The frequency-shifted light is used for modulation to obtain a measurement and control light of the cold atom interferometer.

A single-laser light source system for cold atom interferometers, comprising: a reference light module including a narrow-bandwidth laser and a frequency stabilization module and an optical frequency shift module including a first electro-optic modulator and a first narrow-bandwidth optical-fiber filter. The first electro-optic modulator is connected to the first narrow-bandwidth optical-fiber filter by an optical fiber, and the first electro-optic modulator is connected to the laser by an optical fiber. The first electro-optic modulator receives an initial light from the laser, modulates the initial light by a modulation signal with a preset frequency, and generates sidebands with the preset frequency. The first narrow-bandwidth optical-fiber filter filters the optical signal at the output of the first electro-optic modulator to obtain a frequency-shifted light as the +1-order sideband. The frequency-shifted light is used for modulation to obtain a measurement and control light of the cold atom interferometer.

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.

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.

Disclosed herein is an endpoint detection having an optical bundle configured to emit light through a ceiling of a processing chamber. The optical bundle has a plurality of fibers configured to transmit the light from a light source towards a substrate and is configured to receive light reflected from the substrate. The plurality of fibers include a first emitting fiber and a first receiving fiber. The first receiving fiber is radially disposed at a pairing angle from the first emitting fiber, and is configured to receive light emitted from the first emitting fiber. The plurality of fibers further include a second emitting fiber and a second receiving fiber. The second receiving fiber is radially disposed at the pairing angle from the second emitting fiber. The second receiving fiber is configured to receive light originating from the second emitting fiber. The pairing angle is between about 175 degrees and 185 degrees.

An interferometer arrangement includes a beam splitter (8), two retroreflectors (15, 16), a drive (24) that moves at least one of the retroreflectors to alter an optical path difference between interferometer arms (13, 14), a converging element (18) for reference light, and a reference light detector (19) with at least three detector areas (19a-19d). First and second pairs of detector areas are aligned in respective first and second directions, wherein the first direction, the second direction and a central propagation direction of the reference light at the reference light detector are linearly independent. At least two actuators (9, 10) alter a lateral shear between two reference light partial beams (11, 12), which are reflected back from the interferometer arms and superimposed at the beam splitter, in at least two degrees of freedom. Control electronics (38) control the actuators depending on signals (Sa-Sc) at the detector areas, thereby minimizing the shear.