Abstract: A system for a high resolution optical spectrum analyzer (OSA) using various optical configurations to reduce polarization dependent loss (PDL) is disclosed. The system may include a birefringent element to receive an input optical beam. The birefringent element may then split the optical beam into at least two exit beams. The system may also include an optical configuration comprising at least one optical element. The optical configuration may receive the at least two exit beams from the birefringent element and transform at least one of the two exit beams using the at least one optical element to provide two parallel beams with parallel polarizations. The optical configuration may then output the two parallel beams with parallel polarizations to a downstream optical element, such as a diffraction grating, or other optical element.

Abstract: A system for measuring a target grating includes an illumination source, a reference transmission grating, a pupil filter, and a detector. The illumination source is disposed to generate an incident light beam that illuminates the reference transmission grating. The reference transmission grating splits the incident light beam into a plurality of diffraction orders. The plurality of diffraction orders interrogates a target grating. The reference transmission grating and the target grating are parallel. The pupil filter allows transmission of a subset of diffraction orders of light that has been diffracted and/or reflected from the target grating after being split again by passing through the reference transmission grating. The detector takes a measurement of the subset of diffraction orders of light after transmission through the pupil filter.

Abstract: The present disclosure is a sheet producing device for producing a multi-layer sheet by applying a coating material to a sheet material. The sheet producing device includes a radiation light source that emits radiation light, a division part that divides the radiation light into measurement light to be incident on the multi-layer sheet and reference light with which a reference surface is to be irradiated, and an optical member that emits the measurement light onto the multi-layer sheet and receives the measurement light reflected by the multi-layer sheet. An interference detector that detects interference light between the measurement light reflected by the multi-layer sheet and the reference light reflected by the reference surface, and a thickness calculator that calculates a thickness of the sheet material and a thickness of the coating material of the multi-layer sheet based on the detected interference light are further included.

Abstract: A digital projection and reflected glare reduction system according to various aspects of the present technology may include a digital display device capable of generating a one or two dimensional source grid pattern back-illuminated by a light source to project an image of a source grid onto a retroreflective background. The projected source grid image may then be re-imaged onto the original grid element at a slight offset eliminating the need to generate a separate cutoff grid thereby reducing the amount of time required to setup and adjust the system. The digital display device is also capable of switching between a schlieren visualization capability to some other visualization capability (such as particle tracking velocimetry (PTV), particle imaging velocimetry (NV), temperature sensitive paint measurements (TSP), pressure sensitive paint measurements (PSP), photogrammetry, etc.) allowing for the simultaneous use of two different imaging techniques.

Abstract: A novel and useful electronic gyroscope exploits the Sagnac resulting in a detectable phase or frequency shift when an electromagnetic wave travels inside a rotating medium. These shifts in phase or frequency are measured and used to determine the angular velocity of the rotating medium. Three such media can be positioned in mutually perpendicular planes to detect 3D rotational movement. At least one loop acts as an RF transmission media that accommodates simultaneous bidirectional propagation of RF signals while being capable of separating between signals counter propagating in two opposite directions through the use of a switching matrix. A switching matrix and loop buffer function to sample pulses, amplify them, and reinject them back into one of the loops. A time measurement unit functions to detect the time difference between the counter propagating pulses which is used to calculate the rotation rate of the loop.

Abstract: An optical system uses a sample medium disposed within an optical cavity, receives an input beam that may be non-coherent or coherent, and produces an optical energy from the input beam, by creating birefringent-induced beam components each cavity traversal, forming a mixed quantum state beam for the input beam. The mixed quantum state beam exits the cavity, and the energy distribution of the exiting beam is analyzed over a range of tuned input beam frequencies to uniquely identify circularly birefringent the materials within the sample medium, e.g., amino acids, proteins, or other circular birefringent molecules, biological or otherwise.

Abstract: Techniques for reducing the bias error present in optical gyroscopes is disclosed. Such techniques include at least one path length adjustment member placed in an optical gyroscope resonator, which are configured to modulate the optical path length of the resonator so that bias errors attributable to the optical path length are shifted outside of the bandwidth of the optical gyroscope. In some embodiments, the at least one path length adjustment member includes a plurality of microheaters coupled to the resonator, in which case optical path length modulation is achieved by heating the resonator via the microheaters. Alternatively, a plurality of piezo-electric regions can be placed in the resonator, which enables optical path length modulation through electric field gradients applied to the piezo-electric regions.

Abstract: A method and system are presented for use in measuring on patterned samples, aimed at determining asymmetry in the pattern. A set of at least first and second measurements on a patterned region of a sample is performed, where each of the measurements comprises: directing illuminating light onto the patterned region along an illumination channel and collecting light reflected from the illuminated region propagating along a collection channel to be detected, such that detected light from the same patterned region has different polarization states which are different from polarization of the illuminating light, and generating a measured data piece indicative of the light detected in the measurement. Thus, at least first and second measured data pieces are generated for the at least first and second measurements on the same patterned region. The at least first and second measured data pieces are analyzed and output data is generated being indicative of a condition of asymmetry in the patterned region.

Abstract: Aspects of the present disclosure include methods for adjusting sensitivity of a photodiode in a light detection system. Methods according to certain embodiments include detecting light with a light detection system having a photodiode and an amplifier, determining responsivity of the photodiode over a plurality of wavelengths of light and adjusting one or more parameters of the amplifier in response to the responsivity of the photodiode over the plurality of wavelengths of light. Systems (e.g., particle analyzers) having a light source and a light detection system that includes a photodiode and an amplifier for practicing the subject methods are also described. Non-transitory computer readable storage medium are also provided.

Abstract: A sensing system for monitoring a composition of a downhole fluid in a well, where the sensing system includes: a light source, an optical waveguide, an evanescent field sensing element that is indirect contact with a downhole fluid, and a detector. The light source is operable for emitting a beam and includes a frequency comb generator configured to modify at least a portion of the beam into a sensing comb beam. The evanescent field sensing element provides attenuated internal reflection of the sensing comb beam at the interface between the evanescent field sensing element and the downhole fluid, and the portion of the sensing comb beam interacts with the fluid to form at least a portion of an interacted beam. The detector obtains a spectral distribution of the interacted beam.

Abstract: A covered chamberless particulate detector includes a chamberless detector configured to produce a signal when particulate sensing events occurs, one or more optical emitters configured to emit one or more emitting cones of light, one or more optical sensors defining one or more receiving cones and configured to detect occurrence of particulate sensing events, and a protective cover defining an inside region and an outside region. Each of the one or more emitting cones of light is configured to overlap with each of the one or more receiving cones, thereby creating one or more sensing volumes which may be in the inside region, the outside region, or both regions. The protective cover can be transparent, partially transparent, or opaque, and can include apertures. The optical emitters and detectors can use one or more wavelengths, allowing discrimination of various airborne particulates.

Abstract: A metrology system may include an imaging sub-system including one or more lenses and a detector to image a sample, where the sample includes metrology target elements on two or more sample layers. The metrology system may further include a controller to determine layer-specific imaging configurations of the imaging sub-system to image the metrology target elements on the two or more sample layers within a selected image quality tolerance, where each layer-specific imaging configuration includes a selected configuration of one or more components of the imaging sub-system. The controller may further receive, from the imaging sub-system, one or more images of the metrology target elements on the two or more sample layers generated using the layer-specific imaging configurations. The controller may further provide a metrology measurement based on the one or more images of the metrology target elements on the two or more sample layers.

Abstract: An optical array waveguide grating-type multiplexer and demultiplexer according to an embodiment of the present invention comprise: a first substrate, a plurality of first waveguides disposed on the first substrate to be superposed in the vertical direction, which is the thickness direction of the first substrate; a 1-1st cladding layer disposed between the first substrate and a 1-1st waveguide, which is nearest to the first substrate among the plurality of first waveguides; a 1-2nd cladding layer disposed between the plurality of first waveguides; and a 1-3rd cladding layer disposed on a 1-2nd waveguide, which is furthest from the first substrate among the plurality of first waveguides.

Abstract: Apparatus, systems, and methods associated with remote phase and amplitude spectroscopy in frequency, time, and position with correlated frequency combs are applicable in a variety of applications. Multiple beams can be generated from a single laser source, where, in the frequency domain, the multiple beams are frequency combs with equal repetition rates and shifted in frequency from each other. One or more of the multiple beams can be directed to interact with a sample with another one of the multiple beams used as a reference beam. The interaction can include transmission of one of the multiple beams as a signal beam through the sample, reflection of one of the multiple beams as a signal beam from the sample, or backscattering from the sample. Results from the interaction can be analyzed.

Abstract: The present invention relates to a method, a sensor, a sensor unit and a bank-note processing machine for checking the completeness and/or authenticity of value documents. A value document comprises at least one machine-readable feature substance in at the least two locations. According to the method, the value document is excited at least locally at measuring locations. Furthermore, a feature intensity with respect to the machine-readable feature substance is captured location-resolved at several different locations of the value document. The location-based feature intensities are classified location-based with the help of a threshold value. Furthermore, location-based limits of a location distribution to be expected of the machine-readable feature substance are determined. Finally, a location-based distribution of the classified feature intensities is assessed.

Abstract: Disclosed are a femtosecond laser-based ultrasonic measuring apparatus for a 3D printing process, and a 3D printing system including the apparatus. The apparatus includes a femtosecond laser source for generating a femtosecond laser beam irradiated to inspect a state of a printing object formed by melting a base material by a printing laser beam irradiated from the laser source for 3D printing, a beam splitter for separating the femtosecond laser beam generated by the femtosecond laser source into a pump laser beam and a probe laser beam, an electric/acoustic optical modulator for modulating the pump laser beam, a time delay unit for delaying the probe laser beam, a photo detector for detecting the probe laser beam reflected by the printing object, and a lock-in amplifier for detect an amplitude and a phase of the output signal from the photo detector. The femtosecond laser source is disposed coaxially with a laser source for 3D printing.

Abstract: A quantitative phase image generating method for a microscope, includes: irradiating an object with illumination light; disposing a focal point of an objective lens at each of a plurality of positions that are mutually separated by gaps ?z along an optical axis of the objective lens, and detecting light from the object; generating sets of light intensity distribution data corresponding to each of the plurality of positions based upon the detected light; and generating a quantitative phase image based upon the light intensity distribution data; wherein the gap ?z is set based upon setting information of the microscope.

Abstract: Novel monolithic reflective spatial heterodyne spectrometers (SHS) interferometer systems are presented. Monolithic systems in accordance with the invention have a single supporting structure wherein input optics, output optics, a flat mirror, a roof mirror, and a symmetric grating are affixed. Embodiments of the invention contain only fixed parts, and the optics do not move in relation to the supporting structure. Embodiments of the present invention enables smaller, lighter, and more robust reflective SHS systems as compared to conventional interferometry. Additionally, embodiments of the present invention require less time and skill for construction and maintenance, and is a better economic option. Additional embodiments can include multiple interferometer systems in a single supporting structure.

Abstract: A method and system for authenticating an item includes irradiating the item, the item including a polymer substrate including a polymer material and a doping material and configured to emit a radiation spectrum having a spectral signature in response to the irradiating, the doping material capable of absorbing or scattering radiation at a specific wavelength to generate the spectral signature, detecting the spectral signature, and determining a code associated with the spectral signature.

Abstract: An optical component for an interferometric imaging device, which comprises: an object arm, including a first planar waveguide and a first diffraction grating formed in the first planar waveguide and capable of extracting light from the object arm; a reference arm, comprising a second planar waveguide and a second diffraction grating formed in the second planar waveguide and capable of extracting light from the reference arm; wherein the optical component is configured such that, in use with an optically reflective surface extending parallel to the plane of the optical component between the object arm and the reference arm, at least part of the light extracted from the object arm interferes with at least part of the light extracted from the reference arm.