In an optical position measuring device for detecting the relative position of a first measuring standard and a second measuring standard, movable relative to each other along at least one measuring direction, at a splitting grating, a beam bundle emitted by a light source is split up into at least two partial beam bundles. When passing through scanning beam paths, the partial beam bundles undergo different polarization-optical effects. After the differently polarized partial beam bundles are recombined at a combination grating, a plurality of phase-displaced, displacement-dependent scanning signals is able to be generated from the resulting beam bundle. No polarization-optical components are arranged in the scanning beam paths of the partial beam bundles between the splitting and recombination. To generate the different polarization-optical effects on the partial beam bundles, a conically incident illumination beam bundle impinges upon the splitting grating, the incident illumination beam bundle extending in a plane perpendicular to the measuring direction at an angle other than 0°, the plane of incidence being defined by the grating normal to the splitting grating and the direction of incidence of the illumination beam bundle. The scanning beam paths of the partial beam bundles are arranged in mirror symmetry with respect to the plane of incidence between the splitting and recombination.

The present invention provides the Fabry-Perot (F-P) sensor compromising housing, measuring probe, longitudinal sling block, and displacement converting device. The optic fiber passes through upside sealing ring and extends into upside through hole with the optic fiber end surface disposed at the bottom; the upside of longitudinal sliding block is disposed with reflecting surface, thus a Fabry-Perot cavity is formed between part of the fiber end surface at the bottom of the fiber and the reflecting surface on the upside of longitudinal sliding block. The displacement converting device will convert the lateral slides of the measuring probe into the slides of the longitudinal sliding block, which thus changes the distance from the reflecting surface to the fiber end surface and changes the Fabry-Perot cavity length. Further, the sliding distance of the measuring probe can be calculated after the variation of the Fabry-Perot cavity length measured in according with the Fabry-Perot principle.

A quantum interference device (atomic oscillator) includes: an atom cell that encapsulates an alkali metal; a first light source portion that emits light including a resonance light pair, the resonance light pair being circularly polarized in the same direction and causing the alkali metal to resonate; a second light source portion that emits light including adjustment light, the adjustment light being circularly polarized in a direction opposite to the resonance light pair and causing the alkali metal to resonate; and a light receiving portion that receives the resonance light pair having passed through the atom cell, in which the adjustment light is FM-modulated.

A fiber optic sensing system for determining the position of an object requires a light source, an optical fiber, a fiber optic splitter, a fiber tip lens, an optical detector and signal processing circuitry. Light emitted by the light source is conveyed via optical fiber and the splitter to the lens and onto an object, such that at least a portion of the light is reflected by the object and conveyed via fiber and the splitter to the detector. Signal processing circuitry coupled to the detector determines the position of the object with respect to the lens based on a characteristic of the reflected light. The system is suitably employed with a hydraulic accumulator having a piston, the position of which varies with the volume of fluid in the accumulator, with the system arranged to determine the position of the piston, from which the volume can be calculated.

A heterodyne two-dimensional grating measuring device and measuring method thereof includes a light source, a reading head, a photoelectric receiving module, and a signal processing system. The light source is configured to generate two beams of linearly polarized lights having characteristics of overlapping, polarization orthogonal, and fixed frequency difference. The reading head is configured to receive the two beams of the linearly polarized lights, the two beams of the linearly polarized lights are respectively incident on a surface of a moving two-dimensional measuring grating to generate ±1-order diffracted lights of two dimensions, and the ±1-order diffracted lights are respectively incident to the photoelectric receiving module through the reading head. The photoelectric receiving module is configured to generate beat frequency signals, the signal processing system is configured to perform differential calculation on the beat frequency signals to realize a displacement measurement of measuring grating for four-fold optical subdivision.

The invention pertains to a contactless measurement method for detecting rotation of an object over an axis coinciding with an optical axis of a probe beam. The probe beam is comprised of two monochromatic wavelengths with circular polarizations of opposite chirality, having a frequency difference for providing a heterodyne probe beam. A neutral beam splitter is provided that directs a reflected beam via a polarizer filter towards a first photodetector and that directs a transmitted beam toward a quarter wave plate attached to a rotatable object. A mirror reflects the probe beam, via the same quarter wave plate, back into the neutral beam splitter, which directs the reflected beam via a polarizer filter toward a second photodetector. The rotation is derived from the relative phase difference between the first and second photodetector signals.

An electronic device is described. The electronic device may include a housing, a rotatable crown, and a self-mixing interferometry (SMI) sensor positioned within the housing. The rotatable crown may include an array of retroreflective surface features that reflect incident light back to a light source. Each retroreflective surface feature of the array of retroreflective surface features may be formed as a corner-cube with three perpendicular faces. The SMI sensor or associated processing electronics may compare originally emitted light with reflected light to identify a movement or distance of the rotatable crown with respect to the SMI sensor.

Embodiments disclosed herein include a substrate support having a sensor assembly, and processing chamber having the same. In one embodiment, a substrate support has a puck. The puck has a workpiece support surface and a gas hole exiting the workpiece support surface. A sensor assembly is disposed in the gas hole and configured to detect a metric indicative of a deflection of a workpiece disposed on the workpiece support surface, wherein the sensor assembly is configured to allow gas to flow past the sensor assembly when positioned in the gas hole.

In order to provide an optical encoder with high resolution, the optical encoder includes: a rotary scale provided with a grating pattern having a first radial pattern and a plurality of concentric circular patterns disposed at predetermined intervals; and a light receiving element which detects a first interference fringe formed by the first pattern having a first period in the circumferential direction, a second interference fringe which is diffracted in a direction of the first interference fringe by a grating pattern having a second period in the circumferential direction disposed at a different radial position so that the second interference fringe has a period closer to the first period than the second period.

New platform technologies to actuate and sense force propagation in real-time for large sheets of cells are provided. In certain embodiments the platform comprises a device for the measurement of mechanical properties of cells or other moieties, where device comprises a transparent elastic or viscoelastic polymer substrate disposed on a rigid transparent surface; and a plurality of micromirrors disposed on or in said polymer substrate, wherein the reflective surfaces of the micromirrors are oriented substantially parallel to the surface of said polymer substrate. In certain embodiments the device comprises more than about 1,000,000, or more than about 10,000,000 micromirrors. In certain embodiments the micromirrors comprise a magnetic layer and/or a diffraction grating.