Abstract: Apparatus and methods are described for calibrating an optical system that is used for measuring optical properties of a portion of a subjects body. During a calibration stage, a front surface of a calibration object (300) is illuminated, light reflected from a plurality of points on the calibration object (300) is detected, and intensities of the light reflected from the plurality of points on the calibration object (300) are measured. During a measurement stage, the portion of the subjects body is illuminated, and light reflected from the portion of the subjects body is detected. Measurements performed upon the light that was reflected from the portion of the subjects body are calibrated, using the measured intensities of the light reflected from the plurality of points on the calibration object (300). Other applications are also described.

Abstract: An optical filter includes a pair of reflection films facing each other via a gap, and a gap change portion that changes a distance between the pair of reflection films, wherein the reflection film is formed by a plurality of layered structures, the plurality of layered structures are respectively formed by alternate stacking of high-refractive layers and low-refractive layers having smaller refractive indices than the high-refractive layers and, in the respective layered structures, optical film thicknesses of the high-refractive layers and optical film thicknesses of the low-refractive layers are film thicknesses based on predetermined design center wavelengths set with respect to each of the layered structures, and the design center wavelengths are different with respect to each of the layered structures.

Abstract: Hyperspectral resonant cavity imaging spectrometers and imaging systems incorporating the resonant cavity spectrometers are provided. The spectrometers include an array of photodetectors based on photosensitive semiconductor nanomembranes disposed between two dielectric spacers, each of the dielectric spacers having a thickness gradient along a lateral direction, such that the resonant cavity height differs for different photodetectors in the array.

Abstract: A circuit and method for mitigating multi-path interference in direct detection optical systems is provided. Samples of an optical signal having a pulse amplitude modulated (PAM) E-field are processed by generating a PAM level for each sample. For each sample, the sample is subtracted from the respective PAM level to generate a corresponding error sample. The error samples are lowpass filtered to produce estimates of multi-path interference (MPI). For each sample, one of the estimates of MPI is combined with the sample to produce an interference-mitigated sample.

Abstract: Sensor delivery devices and methods of measuring Fractional Flow Reserve in a patient are disclosed. One sensor delivery device includes a distal sleeve, a proximal portion, and a pressure sensor. The distal sleeve is configured to be advanced through a patient's vasculature over a guidewire. The pressure sensor is located on the distal sleeve or the proximal portion. The pressure sensor is adapted to generate a signal proportional to fluid pressure. The pressure sensor includes a material having a low thermal coefficient of pressure.

Abstract: This disclosure describes a capacitively controlled Fabry-Perot interferometer which comprises a first mirror layer with a first metallic thin-film layer embedded in a first insulating layer and a second mirror layer with a second metallic thin-film layer embedded within a second insulating layer. A control region in the first metallic thin-film layer is at least partly aligned in an actuation direction with a control region in the second metallic thin-film layer. The interferometer also comprises a first control electrode and a first dielectric layer, and the first dielectric layer lies between the first control electrode and at least a part of the control region of the first metallic thin-film layer.

Abstract: A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

Abstract: A multi-pixel spectroscopy sensor for spectral analysis of a sample under test including an array of pixel elements generating a dataset including a plurality of data values corresponding to the pixel elements upon illumination of the sample by a light source. Each of the pixel elements including a stack of layers including first and second reflective structures, a phase tuning element, a detector element, and contact elements. The sensor further includes a read-out circuit connected to each of the contact elements for simultaneous read-out of a plurality of photocurrents for generating and outputting the dataset for the spectral analysis of the sample under test. The phase tuning element of each of the pixel elements is configured for a different wavelength response of the light and each photodetector of the pixel elements is comprised of a semiconductor material.

Abstract: A semiconductor laser module that includes a package accommodating therein a plurality of optical components, includes: a semiconductor laser device that emits laser light toward one end side in the package; an optical fiber having an incident end of the laser light on another end side in the package, the another end being in an opposite direction of an emission direction in which the semiconductor laser device emits the laser light; and a turn-back unit that turns back the laser light toward the another end side in the package, the another end being in the opposite direction of the emission direction in which the semiconductor laser device emits the laser light, and outputs the laser light to the incident end of the optical fiber.

Abstract: Described herein is a wavelength reference device comprising a housing defining an internal environment having a known temperature. A broadband optical source is disposed within the housing and configured to emit an optical signal along an optical path. The optical signal has optical power within a wavelength band of interest. An optical etalon is also disposed within the housing and positioned in the optical path to filter the optical signal to define a filtered optical signal that includes one or more reference spectral features having a known wavelength at the known temperature. The device also includes an optical output for outputting the filtered optical signal.

Abstract: In some implementations, an optical assembly comprises an optical cavity; one or more detectors; and an optical component having an input face and an output face configured to receive an input beam to the input face and to produce one or more primary output beams, and a plurality of secondary output beams from the output face, the secondary output beams resulting from multiple internal reflections within the optical component. At least one of the input face is not perpendicular to the input beam or the output face is not perpendicular to the one or more primary output beams. Each primary output beam is transmitted through the optical cavity perpendicular to at least one surface of the optical cavity, and directed to a respective one of the one or more detectors. Each detector is arranged to exclude at least a portion of each secondary output beam.

Abstract: Herein provided is a radiation dosimeter and associated systems and methods. The radiation dosimeter comprises a light source configured for producing an input optical signal; a resonant cavity coupled to the light source for receiving the input optical signal, the resonant cavity configured for containing a fluid and for producing an output optical signal from the input optical signal indicative of a radiation dose absorbed by the fluid; and a light detector coupled to the optical fiber for obtaining the output optical signal.

Abstract: An integrated optical sensor enables the detection and identification of one or more remote gases using a transmission filter that matches specific absorption features of a remote gas and is detected using a single photodetection element. The sensor comprises an integrated optical component that is characterized by its transmission spectrum which corresponds to absorption or emission features of a target gas over a defined spectral bandpass, and the ability to have a reversibly tunable transmission spectrum. The change in the optical power output from the sensor as the transmission spectrum is tuned is proportional to the optical depth of the target gas absorption lines when viewed with a background light source. The optical power output from the integrated optical component is therefore related to the absorption spectrum of the input light Physical properties of the sensor are tailored to produce a quasi-periodic transmission spectrum that results in a stronger signal contrast for a specific gas.

Abstract: An image sensor with uniform, well-controlled air gaps is provided. A structure that is at least partially filled with organic material may be formed on the image sensor. A hybrid organic/inorganic film layer may be formed over the organic material. The image sensor may then be exposed to energy, which causes the organic material to sublimate through the hybrid film layer, which itself may become a gas permeable layer when exposed to energy. After sublimation, the regions where the organic material was previously filled become air gaps with a low index of refraction. Air gaps formed in this way can be configured over photodiodes as light guides or focusing structures, as concave/convex microlenses, in between photodiodes as isolation structures, in between color filter elements to reduce crosstalk, and/or over microlenses to enhancing focusing power.

Abstract: A wafer includes a substrate layer, a first mirror layer having a plurality of two-dimensionally arranged first mirror portions, and a second mirror layer having a plurality of two-dimensionally arranged second mirror portions. In the wafer, a gap is formed between the first mirror portion and the second mirror portion so as to form a plurality of Fabry-Perot interference filter portions. A wafer inspection method according to an embodiment includes a step of performing faulty/non-faulty determination of each of the plurality of Fabry-Perot interference filter portions, and a step of applying ink to at least part of a portion overlapping the gap when viewed in a facing direction on the second mirror layer of the Fabry-Perot interference filter portion determined as faulty.

Abstract: An optical signal transceiver in a transistor outline package includes a component base, a laser device, a first wavelength division multiplexing prism and a second wavelength division multiplexing prism, a first photodetector, and a second photodetector. The component base is inside the transistor outline package and supports the laser device, the laser device emitting light to the outside of the transistor outline package. The first and second prisms and the first photodetector and the second photodetector are also located on the component base. Light output as optical signals sequentially pass through the first and second multiplexing prisms. The first input optical signal is transmitted to the first photodetector through the first prism, and the second input optical signal passes through the first prism and is passed on to the second photodetector via the second prism.

Abstract: Disclosed herein are electronic devices having touch input surfaces. A user's touch input or press on the touch input surface is detected using a set of lasers, such as vertical-cavity surface-emitting lasers (VCSELs) that emit beams of light toward the touch input surface. The user's touch causes changes in the self-mixing interference within the VCSEL of the emitted light with reflected light, such as from the touch input surface. Deflection and movement (e.g., drag motion) of the user's touch is determined from detected changes in the VCSELs' operation due to the self-mixing interference.

Abstract: A system comprises a particle sensor assembly, which includes a light source that transmits a light beam into an external interrogation air region; a set of receive optics that provides a receive channel, the receive optics configured to collect a scattered portion of the light beam from a particle in the interrogation air region; and an optical detector that receives the collected scattered portion. The optical detector measures a signal intensity as a function of time from the scattered portion, with the signal intensity indicating a particle size and a signal duration indicating motion of the particle through the interrogation air region. A processor is in communication with the optical detector and is operative to determine a transit time of the particle through the interrogation air region based on the signal duration, and compute an airspeed based on parameters comprising the transit time and a size of the light beam.

Abstract: A fiber optic sensor and a related method of manufacture are provided. The fiber optic sensor includes an embedded optical fiber contained within a metal diaphragm assembly, where the terminal end of the optical fiber is positioned opposite a diaphragm. The method includes forming a metal-embedded optical fiber by ultrasonic additive manufacturing and securing the metal-embedded optical fiber to a housing having a diaphragm that is opposite of the terminal end of the optical fiber. The sensor can provide extremely accurate pressure measurement at high temperatures and in highly corrosive media. An optical fiber-based pressure sensing system is also provided.

Abstract: Tunable MEMS etalon devices comprising: a front mirror and a back mirror, the front and back mirrors separated in an initial pre-stressed un-actuated etalon state by a gap having a pre-stressed un-actuated gap size determined by a back stopper structure in physical contact with the front mirror and back mirrors, the etalon configured to assume at least one actuated state in which the gap has an actuated gap size gap greater than the pre-stressed un-actuated gap size; an anchor structure, a frame structure fixedly coupled to the front mirror at a first surface thereof that faces incoming light, and a flexure structure attached to the anchor structure and to the frame structure but not attached to the front mirror, and a spacer structure separating the anchor structure from the back mirror, and wherein the front mirror and the spacer structure are formed in a same single glass layer.

Abstract: A multi-channel sensing system is disclosed. The multi-channel sensing system includes a multi-channel sensor connector that wavelength-divides an optical pulse output from a pulsed laser into a plurality of channels in a spectrum domain, transmits each of a plurality of optical sub-pulses generated from the wavelength division to a channel path allocated for each channel in multi-channel paths, multiplexes the plurality of optical sub-pulses passed through the multi-channel paths and outputs an optical signal including the multiplexed optical sub-pulses; and a multi-channel optical phase detector that receives the optical signal output from the multi-channel connector and a reference signal which is synchronized to the pulse laser, and detects a channel-specific electrical signal that corresponds to a timing error between each of the plurality of optical sub-pulses included in the optical signal and the reference signal. At lease one of sensors is connected to at least one of the multi-channel paths.

Abstract: A method to measure the refractive index of a sample, includes: providing a plasmonic sensor including a sensing surface in contact with the sample; providing an optical resonator, the plasmonic sensor being integrated therein as a reflecting surface; providing a first input field of electromagnetic radiation as a primary carrier; providing a second input field of electromagnetic radiation as a secondary carrier having a second frequency different from the first and defined as: second frequency=first frequency+?v and having a TE and/or a TM polarized component; impinging simultaneously with the first and second input field the plasmonic sensor; tuning the frequency of the first field and/or the value of ?v; detecting a resonator output power corresponding to the first and second intra-cavity fields resonating; determining a difference between the first and the second resonating frequencies; and calculating the refractive index of the sample from the difference.

Abstract: Systems for protein quantitation using a Fabry-Perot interferometer. In one arrangement, a quantitation device includes an infrared source, a sample holder, and a Fabry-Perot interferometer positioned to receive infrared radiation from the source passing through a sample on the sample holder. A band pass optical filter sets the working range of the interferometer, and radiation exiting the interferometer falls on a detector that produces a signal indicating the intensity of the received radiation. A controller causes the interferometer to be tuned to a number of different resonance wavelengths and receives the intensity signals, for determination of an absorbance spectrum.

Abstract: An optical inspection device includes: a wafer support unit configured to support a wafer in which a plurality of Fabry-Perot interference filter portions are formed, each of the plurality of filter portions in which a distance between the first mirror portion and the second mirror portion facing each other varies by an electrostatic force, the wafer support unit configured to support the wafer such that a direction in which the first mirror portion and the second mirror portion face each other follows along a reference line; a light emission unit configured to emit light to be incident on each of the plurality of filter portions along the reference line; and a light detection unit configured to detect light transmitted through each of the plurality of filter portions along the reference line. The wafer support unit has a light passage region that allows light to pass along the reference line.

Abstract: A spectroscopic measurement apparatus includes a fixed substrate, a movable substrate, and a wavelength variable interference filter which includes an electrostatic actuator for changing the gap dimension between the substrates, a vibration disturbance detection unit which detects vibration added to the wavelength variable interference filter, and a bias driving unit which applies a feed-forward voltage based on a detected value of the vibration disturbance detection unit to the electrostatic actuator.

Abstract: Provided is a filter controlling expression derivation method including: preparing a Fabry-Perot interference filter of which distance between a fixed mirror and a movable mirror is controlled by balancing an electrostatic force and an elastic force; deriving a relational expression between a deflection amount and an elasticity index in which the elasticity index of the movable mirror is described as a quadratic or higher-order polynomial with the deflection amount of the movable mirror as a variable by performing predetermined measurement; and deriving a relational expression between a transmission wavelength of light transmitted through the Fabry-Perot interference filter and the voltage as a filter controlling expression based on the relational expression between the deflection amount and the elasticity index and a relational expression between the electrostatic force and the elastic force.

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.

Abstract: A spectroscopic apparatus includes a splitter that receives a first detected signal output from a sample to which an incident beam is irradiated, and outputs a reflected signal and a second detected signal by splitting the first detected signal, and a signal processor that receives the reflected signal and the second detected signal, and extracts a Raman signal from the second detected signal in response to the received reflected signal.

Abstract: Provided is a spectral imaging apparatus. The spectral imaging apparatus includes: an optical filter including a plurality of band filter units having different center wavelengths; a sensing device configured to receive light passing through the optical filter; an imaging lens array including a plurality of lens units which respectively correspond to the plurality of band filter units and each implement imaging on the sensing device; and a transparent substrate which is apart from the sensing device. At least one of the optical filter and the imaging lens array is provided on the transparent substrate.

Abstract: Provided is a non-transitory computer-readable recording medium recording an optical measurement control program in a light detection device, the program causing a computer to execute a process of measuring light to be measured by acquiring an electric signal output from the light detector, the optical measurement control program causing the computer to function as: a voltage control unit controlling the potential difference generated between the pair of mirrors to gradually increase until the potential difference reaches a set potential difference corresponding to a wavelength of the light to be measured before the acquisition of the electric signal is started; and a signal acquisition unit acquiring the electric signal in a state where the voltage control unit allows the set potential difference to be generated between the pair of mirrors.

Abstract: A diagnosis assistance device assists a diagnosis of an optical characteristic measurement device which operates on the basis of the content of setting stored in a setting storage unit of an optical characteristic measurement device, and includes a first storage unit, a second storage unit, a processing unit, a first command unit, a diagnosis unit, and a second command unit. The first storage unit stores in advance first setting information which indicates the content of setting at the time of diagnosis. The processing unit performs processing of acquiring, from the setting storage unit, second setting information which is stored in advance in the setting storage unit and indicates the content of setting at the time of use, and storing the acquired second setting information in the second storage unit. The first command unit issues a command to store the first setting information stored in the first storage unit in the setting storage unit.

Abstract: A light detection device includes a package including a window, a Fabry-Perot interference filter for transmitting light incident from the window in the package, and a light detector for detecting the light transmitted by the Fabry-Perot interference filter in the package. The Fabry-Perot interference filter includes: a substrate having a first surface on the window side and a second surface on the light detector side; a first layer structure arranged on the first surface, the first layer structure having a first mirror and a second mirror; and a lens unit integrally formed on the second surface side, the lens unit for condensing the light transmitted by the first mirror and the second mirror onto the light detector.

Abstract: A phase retarder and an optical comb filter are disclosed. The phase retarder includes a polarization beam splitter, a first air arm, and a second air arm, where the polarization beam splitter is configured to decompose a beam into a first light component propagated in a first direction and a second light component propagated in a second direction, the first direction is perpendicular to the second direction; the first air arm is disposed on a second side wall of the polarization beam splitter, and is configured to receive the first light component and reflect it back; and the second air arm is disposed on a third side wall of the polarization beam splitter, and is configured to receive the second light component and reflect it back. Two light components interfere, and the interference light is emitted from a fourth side wall of the polarization beam splitter.

Abstract: The present invention provides an infrared detector pixel structure and manufacturing method thereof. The bottom portion of a silicon substrate is bonded with a bonding substrate, an infrared absorbing layer in the bonding substrate is used for absorbing a part of infrared light, a closed cavity filled with infrared-sensitive gas is set in the silicon substrate, and a piezoelectric transforming unit is bonded onto the closed cavity. When the infrared-sensitive gas absorbs the infrared light to expand, the infrared sensitive gas will press the piezoelectric transforming unit, which causes piezoelectric signal generated by the piezoelectric transforming unit to be changed, thereby achieving the detection on the infrared light.

Abstract: A laser radar apparatus includes: a scanner capable of beam scanning at a first angular speed; a measurable wind distance calculator monitor to calculate and to monitor a measurable wind distance based on wind measurement data obtained through beam scanning by the scanner; an optical axis angular correction amount deriver to derive an optical axis angular correction amount being able to obtain the largest distance of the measurable wind distance, based on a first angular speed and the wind measurement data obtained through beam scanning at a second angular speed lower than the first angular speed, when decrease of the measurable wind distance is detected by the measurable wind distance calculator monitor; and an optical axis corrector to correct an optical axis angular deviation between transmitted light and reception light, based on the optical axis angular correction amount.

Abstract: A process for characterizing an optical source including a fixed cavity having a free spectral range, the process including: generating a first radiation; receiving at least a portion of this first radiation by at least one sensor; measuring a signal by each sensor and for each scanned state of the source; on the basis of the signals measured, and for each scanned state of the source, calculating a first data item which represents the wavelength of the first radiation, the calculation including, for each scanned state of the source, a selection of a selected value of the first data item from a plurality of possible values, the selection including the elimination of the values of the first data item which do not correspond to a modulo constant of the free spectral range of the fixed cavity expressed according to the units of the first data item.

Abstract: A static pressure measurement probe system comprises: a base to be fixed onto the cockpit of an aircraft; at least one local pressure tapping formed through the base and coupled to a pressure measurement sensor; for each local pressure tapping, at least two assemblies each comprising an optical window that is transparent to a laser radiation and a laser anemometry probe configured to take anemometry measurements in an imaginary cylinder centred on the local pressure tapping and of a diameter less than 3 cm and of a height less than 4 cm counted from the outer end of the local pressure tapping, so that the measurements are within the airflow limit layer.

Abstract: An optical scanning device, an image display device, a heads-up display, and a mobile object. The optical scanning device includes a light source configured to emit scanning light, a light quantity adjuster provided with a plurality of optical attenuators having different light transmittances, the light quantity adjuster configured to change a light-intensity of the scanning light by switching one of the plurality of optical attenuators placed on an optical path, by movement of the light quantity adjuster, to scan a to-be-scanned surface using the scanning light passed through the light quantity adjuster, and a home position sensor configured to detect that the light quantity adjuster is present at a predetermined position. The light source starts emitting the scanning light after one of the plurality of optical attenuators is placed on the optical path at a time of startup.

Abstract: Optical arrangements for processing a workpiece include a fiber laser arrangement for emitting laser radiation, a fiber arrangement directly coupled to the fiber laser arrangement and configured to guide the laser radiation in a direction to the workpiece to be processed, the fiber arrangement including a transport fiber having a fiber core and at least one fiber cladding surrounding the fiber core, and at least one coupling device for coupling a portion of the laser radiation guided in the fiber arrangement into at least one fiber cladding of the transport fiber. The coupling device has a spectral bandwidth of at least the same magnitude as a spectral bandwidth of the laser radiation. The fiber laser arrangement is configured to change a beam profile of the guided laser radiation to shift the spectral bandwidth of the laser radiation relative to the spectral bandwidth of the coupling device.

Abstract: A Fabry-Perot interference filter includes a fixed mirror and a movable mirror disposed opposite to the fixed mirror via a gap, distance between the fixed mirror and the movable in a light transmission region being adjusted by electrostatic force. A plurality of first annular grooves surrounding the light transmission region and a plurality of first through-holes opening to the gap side and the opposite side are formed at a surrounding portion surrounding the light transmission region in the movable mirror.

Abstract: A spectral filter (10) is provided with a long-pass filter (12) and a short-pass filter (13). The long-pass filter (12) has a film thickness gradient GL wherein film thickness increases monotonically in a single direction, and transmits light of a wavelength region longer than a cut-off wavelength WL. The short-pass filter (13) has a film thickness gradient GS wherein film thickness increases monotonically in a single direction, and transmits light of a wavelength region shorter than a cut-off wavelength WS. The long-pass filter (12) and the short-pass filter (13) are overlapped such that the single directions match each other. At the positions in the single directions, a transmittance peak is formed by the cut-off wavelength WL being shorter than the cut-off wavelength WS. The film thickness gradient GL is greater than the film thickness gradient GS.

Abstract: A tunable light source includes a substrate; a light source; a wavelength selecting device that selects, according to a control signal, output light with a specific wavelength from light output from the light source; a wavelength filter that is disposed on the substrate, filters the output light, and outputs the filtered light; a light-receiving device that receives the filtered light from the wavelength filter; and a controller configured to generate the control signal based on an output transmittance corresponding to a quantity of the received light received by the light-receiving device, a first transmittance corresponding to a target wavelength, a second transmittance corresponding to a shorter-wavelength limit of a control range including the target wavelength, and a third transmittance corresponding to a longer-wavelength limit of the control range, and output the generated control signal to the wavelength selecting device.

Abstract: In some embodiments, at least one processor is employed to determine a boundary of a survey area. Data representative of the locations of measurement points adjacent to or outside of the survey area is received, as well as data representative of wind direction at the measurement points. The boundary of the survey area is determined according to the data representative of wind direction and a maximum detection distance value representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential source can be detected.

Abstract: A device may include a first photodetector to generate a first current based on an optical power of an optical beam. The device may include a beam splitter to split a portion of the optical beam into a first beam and a second beam. The device may include a wavelength filter to filter the first beam and the second beam. The wavelength filter may filter the second beam differently than the first beam based on a difference between an optical path length of the first beam and an optical path length of the second beam through the wavelength filter. The device may include second and third photodetectors to respectively receive, after the wavelength filter, the first beam and the second beam and to generate respective second currents.

Abstract: A narrow bandpass filter that may be used in a mid-infrared sensor for monitoring a species, which may be a component of a fluid or a solid material. The filter comprises a cavity comprising a low refractive index material. By providing a high ratio of low refractive index material in the filter with respective to high refractive index material, the filter is configured so that wavelength transmission remains constant with varying temperature. Materials used for the low and/or high refractive index provide a temperature invariant filter that transmits mid-infrared spectra without serious degradation.

Abstract: An observation apparatus (100) includes an observing optical system (101) capable of obtaining an image of a measurement target present in a gap included in a device (1). One end of the gap included in the device (1) is wider than the other end thereof, and upon light beam irradiation to the device (1), an interference fringe appears in the gap. The observing optical system (101) irradiates the gap included in the device (1) with a plurality of light beams having different wavelengths to cause a plurality of interference fringes to appear in the gap. Then the observing optical system (101) obtains an image of the plurality of interference fringes.

Abstract: An optical comb filter, comprising an input/output collimator (50), an output collimator (60), a spectroscope (10), and first, second and third GT resonant cavities (20, 30, 40), wherein each GT resonant cavity comprises a transparent solid block coated with a membrane layer and a spacing part, a through hole is provided on the transparent solid block, and the transparent solid block and the spacing part form a hollow cavity; and rectangular orientation of an insertion loss curve is realized, and the bandwidth utilization rate is high.

Abstract: Techniques for controlling an optical system include accessing a measured value of a property of a particular pulse of a pulsed light beam emitted from the optical system, the property being related to an amount of coherence of the light beam; comparing the measured value of the property of the light beam to a target value of the property; determining whether to generate a control signal based on the comparison; and if a control signal is generated based on the comparison, adjusting the amount of coherence in the light beam by modifying an aspect of the optical system based on the control signal to reduce an amount of coherence of a pulse that is subsequent to the particular pulse.

Abstract: In one embodiment, a laser system includes a seed laser diode configured to produce a free-space seed-laser beam. The laser system also includes a pump laser diode configured to produce a free-space pump-laser beam. The laser system further includes an optical-beam combiner configured to combine the seed-laser and pump-laser beams into a combined free-space beam and a focusing lens configured to focus the combined beam. The laser system also includes an optical gain fiber that includes an input end configured to receive the focused beam. The laser system also includes a mounting platform, where one or more of the optical-beam combiner, the focusing lens, and the input end of the gain fiber are mechanically attached to the platform.

Abstract: A spectroscopic sensor 1 comprises an interference filter unit 20, having a cavity layer 21 and first and second mirror layers 22, 23 opposing each other through the cavity layer 21, for selectively transmitting therethrough light in a predetermined wavelength range according to an incident position thereof; a light-transmitting substrate 3, arranged on the first mirror layer 22 side, for transmitting therethrough light incident on the interference filter unit 20, a light-detecting substrate 4, arranged on the second mirror layer 23 side, for detecting the light transmitted through the interference filter unit 20, and a first coupling layer 11 arranged between the interference filter unit 20 and the light-transmitting substrate 3. The cavity layer 21 and the first coupling layer 11 are silicon oxide films.