Abstract: A laser apparatus, a measurement apparatus, and a measurement method are provided in which the laser apparatus outputs a frequency-modulated laser beam with a plurality of modes and includes: an optical cavity that has a gain medium for amplifying a light to be input, and an optical SSB modulator for shifting a frequency of the light amplified by the gain medium: and a control part that controls the optical SSB modulator to shift a frequency of a light to be input to the optical SSB modulator.

Abstract: Systems and methods for embodiments having an extra thick ultraviolet durability coating are described herein. For example, a system may include a laser block assembly. The system may also include a cavity in the laser block assembly. Further, the system may include a plurality of multilayer mirrors in the cavity. In certain embodiments, at least one multilayer mirror of the plurality of multilayer mirrors may include a plurality of alternating layers of a first optical material having a high index of refraction and a second optical material having a first low index of refraction. Additionally, the at least one multilayer mirror may include a multilayer durability coating disposed on the plurality of alternating layers.

Abstract: The range of measurement in spectrally controlled interferometry (SCI) is extended by superimposing multiple modulations on the low-coherence light used for the measurement. Optimally, a spectrally controllable light source modulated sinusoidally with low spectral frequency is combined with a delay line, such as provided by a Michelson interferometer. The resulting light is injected into a Fizeau interferometer to generate localized fringes at a distance corresponding to the effect of the spectrally modulated source combined with the optical path difference produced by the delay line. The combination provides a convenient way to practice SCI with all its advantages and with a range that can be extended to the degree required for any practically foreseeable application. Alternatively, a single source capable of multiple modulations can be used instead of a separate second modulator component.

Abstract: A system that may include a radiation source to generate a beam of coherent radiation; traveling lens optics to focus the beam to generate multiple spots on a surface of a sample and to scan the spots together over the surface; collection optics to collect the radiation scattered from the multiple spots and to focus the collected radiation to generate a pattern of interference fringes; and a detection unit to detect changes in the pattern of interference fringes.

Abstract: A polarization-maintaining fully-reciprocal bi-directional optical carrier microwave resonance system and an angular velocity measurement method thereof. In the system, highly stable optical carrier microwaves are generated in a clockwise direction and a counterclockwise direction in the same resonant cavity, and are used to measure the angular velocity of rotation of a carrier apparatus. A fully reciprocal ring-shaped resonant cavity structure is used to achieve a fully reciprocal bi-directional optical resonance system. A polarization state separation technique is used to separate an optical signal into two wavelengths, and optical signals with perpendicular polarization states are transmitted in opposite directions in a sensing ring, thereby improving the measurement capability of the sensing ring. Bi-directional optical carrier microwave resonance is achieved by using a phase tracking structure and a regenerative mode locking technique.

Abstract: A pixelated color mask is combined with a pixelated polarization mask in dynamic interferometry. The color mask includes a wavelength-selective bandpass filter placed in front of each camera pixel such that each set of contiguous four camera pixels is covered by two green bandpass filters, a red bandpass filter, and a blue bandpass filter. The pixelated phase mask is coupled to the color filters such that one polarization filter covers one set of color filters. At least three polarization filters are used to calculate phase. In addition, the color signals can be used, for example, to encode the motion of the interferometer, to provide very high speed autofocus or tip/tilt feedback, to create a color image of the object being measured, to automatically focus the system at different positions for different measurements conducted with different color sources, and to perform heterodyne interferometry with a single, vibration-immune measurement.

Abstract: An optical position-measurement device includes a reflection measuring standard and a scanning unit, which is movable in relation thereto in at least one measurement direction. The reflection measuring standard has an incremental measuring graduation and a reference marking in at least one reference position. In addition to scanning device(s) for the incremental signal generation, the scanning unit includes for the reference signal generation at least one light source, imaging optics, a diaphragm structure arranged in a diaphragm plane, and a plurality of detector elements. Via the imaging optics, imaging of the reference marking onto the diaphragm structure is implemented. The reference marking is provided on the reflection measuring standard and is integrated into the incremental measuring graduation. In addition, the imaging optics has a variable, object-side focal length along a transversal direction oriented perpendicular to the measurement direction.

Abstract: A system for testing an optical surface, the system comprising a non-coherent light source, a detector, a test plate positioned between the non-coherent light source and the optical surface, the test plate separated from the optical surface by a gap, and a processor. The processer is configured to cause the non-coherent light source to illuminate the test plate and optical surface with non-coherent light, control the detector to capture an interferogram produced by interference between light reflected from the test plate and light reflected from the optical surface, and perform quantitative analysis on the interferogram to characterize aberrations in the optical surface.

Abstract: A microscope comprising a coherent light source producing a coherent light beam, a light beam guide system comprising a beam splitter configured to split the coherent light beam into a reference beam and a sample illumination beam, a sample holder configured to hold a sample to be observed, a sample illumination device configured to direct the sample illumination beam through the sample and into a microscope objective, a beam reuniter configured to reunite the reference beam and sample illumination beam after passage of the sample illumination beam through the sample to be observed, and a light sensing system configured to capture at least phase and intensity values of the coherent light beam downstream of the beam reuniter.

Abstract: A method of determining a refractive index of a material sample comprises removably mounting the material sample into a sample holder having a thermal control mechanism, a thermal expansion compensation mechanism, and a rotation mechanism; projecting a laser beam into the material sample, wherein the material sample has a predetermined orientation and temperature, wherein the material sample has parallel sides defining parallel planes for entry and exit of the laser beam into and out of the material sample; collecting a refracted laser beam from the material sample, and determining the refractive index for the material sample at the predetermined temperature. The laser beam may be a visible laser and/or an infrared laser. The thermal control mechanism comprises a thermal controller coupled to an induction coil apparatus and a temperature sensor. The sample holder comprises a refractory metal consisting of one or more of a niobium/molybdenum alloy and a tantalum/tungsten alloy.

Abstract: Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. The narrow-band light beam is passed through an optical filter. The optical filter has complementary and monotonically-varying transmission and reflection coefficients within a predetermined band of wavelengths. The predetermined band of wavelengths includes the wavelength of the narrow-band light beam. A first photodetector detects amplitude of a first portion of the narrow-band light beam transmitted by the optical filter. A second photodetector detects amplitude of a second portion of the narrow-band light beam reflected by the optical filter. The wavelength of the narrow-band light beam is determined, based on a ratio of the determined amplitudes of the first and second portions of the narrow-band light beam transmitted and reflected, respectively.

Abstract: A system for stabilizing a scale factor associated with an optic rotation sensor comprises an optic rotation sensor that generates an optic signal in response to a rotation of the optic rotation sensor. A sensor detection system produces a rotation signal as a function of the optic signal and rotation of the optic rotation sensor. A first waveguide guides a portion of the optic signal for an interaction length, and produces a first processed optic signal. A second waveguide receives a portion of the optic signal from first waveguide through evanescent coupling, and produces a second processed optic signal. A wavemeter detector receives the optic signals and measures the effective interferometric wavelength (EIW) of the light based on the optic signals. A scale factor correction system receives the rotation signal and the EIW, and measures the correct rotation signal by processing the rotation signal and the EIW.

Abstract: Technologies for a high resolution and wide swath spectrometer are disclosed. In the illustrative embodiment, an inverted image slicer converts a linear field of view into a grid shape, allowing for an interferometer of a Fourier transform spectrometer to operate on a narrow range of field of views, improving the average spectral resolution of the spectrometer.

Abstract: An infrared spectrometer for operation in the mid-infrared spectral range is presented, where the spectrometer includes a Bragg-mirror-based spectral filter that is operative for providing an interrogation signal whose spectral content is dispersed along a first direction at a filter aperture. The filter aperture is imaged through a sample by a thermal-imaging camera to create a focused image that is based on the interrogation signal and the absorption characteristics of the sample. As a result, embodiments in accordance with the present disclosure can be smaller, less complex, and less expensive than infrared spectrometers known in the prior art.

Abstract: An interferometer system, including a heterodyne interferometer and a processing system. The heterodyne interferometer is arranged to provide a reference signal and a measurement signal. The reference signal has a reference phase. The measurement signal has a measurement phase and an amplitude. The processing system is arranged to determine a cyclic error of the heterodyne interferometer based on the reference phase, the measurement phase and the amplitude.

Abstract: Colorimeter having first and second illumination units disposed symmetrically to a reference line in a prescribed plane, first and second light-receiving parts disposed symmetrically to the reference line in the prescribed plane, a calculation unit for determining color information about a measurement object, and an opposing wall that opposes the measurement object when it is measured. The opposing wall has an abutting part that abuts the measurement object when it is measured. The abutting part has a pair of first abutting parts disposed on two sides of a measurement opening to flank the measurement opening; and a pair of second abutting parts disposed on an orthogonal line orthogonal to a first-abutting-part connection line that connects the pair of first abutting parts to each other, the pair of second abutting parts being disposed on two sides of the first-abutting-part connection line to flank the first-abutting-part connection line.

Abstract: An apparatus for particulate matter (PM) measurement includes a first light source to generate a first light beam and a second light source disposed at a first distance from the first light source to generate a second light beam in parallel to the first light beam to illuminate a PM. The apparatus further includes a first light detector to measure a first timing corresponding to a first self-mixing signal resulting from a reflection and/or back-scattering of the first light beam from a PM, and a second light detector to measure a second timing corresponding to a second self-mixing signal resulting from a reflection and/or back-scattering of the second light beam from the PM. A processor can determine a first velocity of the PM based on a spatial separation between centers of the first light beam and the second light beam and a temporal separation between the first timing and the second timing.

Abstract: The present inventive concepts relate to an inspection apparatus that snapshots an interference image pattern having a high spatial carrier frequency produced from a one-piece off-axis polarimetric interferometer and that precisely and promptly measures a Stokes vector including spatial polarimetric information. The inspection apparatus dynamically measure in real-time a two-dimensional polarization information without employing a two-dimensional scanner.

Abstract: An optical coherence tomographic device may include a light source, a measurement light generator, a reference light generator, an interference light generator, an interference light detector, and a processor. The interference light detector may include a first and second detector that convert interference light to interference signals, a first signal processing unit that samples the interference signal from the first detector, and a second signal processing unit that samples the interference signal from the second detector. Each of the first and second signal processing units may sample the interference signal at a timing from outside. Light generated by the measurement light generator may at least include first and second correction light. The processor may correct a time lag between sampling timings of the first and second signal processing units by using a first and second correction signal converted from the first and second correction light.

Abstract: Novel monolithic cyclical reflective spatial heterodyne spectrometers (CRSHS) are presented. Monolithic CRSHS in accordance with the invention have a single frame wherein a flat mirror, roof mirror, and symmetric grating are affixed. The invention contains only fixed parts; the flat mirror, roof mirror, and symmetric grating do not move in relation to the frame. Compared to conventional CRSHS known in the art, the present invention enables much smaller and lighter CRSHS, requires less time and skill for maintenance, and is a better economic option. The disclosed invention may include fixed field-widening optical elements or a fiber-fed assembly.