Abstract: A method for monitoring changes in a gap which corresponds to changes in a particular environmental parameter using a tunable laser and interferometer at high frequency is disclosed. The laser light provided to the interferometer is swept through a small range of wavelengths. Light modulated by the interferometer is detected and a non-sinusoidal light intensity output curve is created, a reference point on the curve identified and subsequent sweep of the laser performed. The difference in time, wavelength, or frequency at the occurrence of the reference point between the two sweeps allows for measuring the relative changes in the gap and, as a result, the change in the environmental parameter.

Abstract: Optical filters tunable for both center wavelength and bandwidth, having applications such as in astronomy, remote sensing, laser spectroscopy, and other laser-based sensing applications, using Michelson interferometers or Mach-Zehnder interferometers modified with Gires-Tournois interferometers (“GTIs”) are disclosed. A GTI nominally has unity magnitude reflectance as a function of wavelength and has a phase response based on its resonator characteristics. Replacing the end mirrors of a Michelson interferometer or the fold mirrors of a Mach-Zehnder interferometer with GTIs results in both high visibility throughput as well as the ability to tune the phase response characteristics to change the width of the bandpass/notch filters. A range of bandpass/bandreject optical filter modes, including a Fabry-Perot (“FP”) mode, a wideband, low-ripple FP mode, a narrowband notch/bandpass mode, and a wideband notch/bandpass mode, are all tunable and wavelength addressable.

Abstract: Light, such as from an analyte-wavelength converter or other optical sensor, is propagated to a detector or transmission structure with an entry surface and with output positions such as in an exit surface. For example, the position of light output by such a detector can be used to detect presence of an analyte such as a biomolecule or chemical. Or relative quantities of photons provided at positions of the exit surface can indicate analyte information such as presence, absence, quantity, or concentration. The detector or transmission structure can have a laterally varying energy transmission function, such as with a constant gradient or a step-like gradient. At the exit surface of the transmission structure, a photosensor array or position sensor can sense transmitted light or output photons, and, in response, circuitry can provide signals indicating the analyte information.

Abstract: A micro-optical fiber tip based sensor system for pressure, acceleration, and pressure gradient measurements in a wide bandwidth, the design of which allows for multiplexity of the input side of the system is based on micro-electromechanical fabrication techniques. The optical portion of the system is based on low coherence fiber-optic interferometry techniques which has a sensor Fabry-Perot interferometer and a read-out interferometer combination that allows a high dynamic range and low sensitivity to the wavelength fluctuation of the light source. A phase modulation and demodulation scheme takes advantage of the Integrated Optical Circuit phase modulator and multi-step phase-stepping algorithm for providing high frequency and real time phase signal demodulation. The system includes fiber tip based Fabry-Perot sensors each of which has a diaphragm that is used as a transducer.

Abstract: A Fabry-Perot cavity filter includes a first mirror and a second mirror. A gap between the first and the second mirror monotonically varies as a function of width of the filter. This filter may be used with photodetector and a channel selection filter in an optical device, such as a spectrum analyzer. The channel selection filter may be a metal nanooptic filter array which includes plurality of subwavelength apertures in a metal film or between metal islands.

Abstract: A pressure sensor (100) and system for measuring pressure changes, especially in harsh environments, is described. The pressure sensor has a Fabry-Perot optical cavity formed within a tube (115) with a partial reflective mirror (130) provided by an end of an optical fiber (105) and a reflective mirror (135) provided by an end of a plug (120), with a gap (125) formed between. The pressure sensor may be disposed within a sensing chamber of a housing having an opening into the environment to be monitored. Alternatively, an isolator means may be used to isolate the sensor from the environment while communicating pressure changes to the sensing chamber. In another embodiment, the sensing chamber is filled with a compressible non-flowing material.

Abstract: There is provided a pointing device including a light source that provides incident light for illuminating a front surface of a substrate at a predetermined angle of incidence, the substrate having a rear surface as well as the front surface and being transparent to the wavelength of the incident light, a detector that detects the intensity of speckle light from the front and rear surfaces, the speckle light generated from the incident light, and legs that are in contact with the substrate and charge the front surface of the substrate through friction between the legs and the substrate.

Abstract: A spectral filter includes a two-dimensional array of Fabry-Perot cavity structures, a controller, and a sampling circuit used to switch the Fabry-Perot cavity. The filter receives an incoming image, the sampling circuit switches the cavity to generate a filter image, and the filtered image is detected by the photodetectors to convert a filtered image into digital data. The controller coordinates all the image capture functions of the spectral filter.

Abstract: A method and apparatus are disclosed for measuring a characteristic, e.g. spectral bandwidth, of a light beam. The apparatus may comprise an etalon for generating an interference pattern having at least one light cone, an arrangement of detector elements, the arrangement receiving a portion of the light cone and producing a signal indicative of the characteristic; and an auxiliary detector positioned to receive a portion of the light cone and produce a signal indicative of an alignment between the etalon and the linear arrangement.

Abstract: A tunable optical cavity can be tuned by relative movement between two reflection surfaces, such as by deforming elastomer spacers connected between mirrors or other light-reflective components that include the reflection surfaces. The optical cavity structure includes an analyte region in its light-transmissive region, and presence of analyte in the analyte region affects output light when the optical cavity is tuned to a set of positions. Electrodes that cause deformation of the spacers can also be used to capacitively sense the distance between them. Control circuitry that provides tuning signals can cause continuous movement across a range of positions, allowing continuous photosensing of analyte-affected output light by a detector.

Abstract: At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by a Fabry-Pérot etalon, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto.

Abstract: At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by an interferometer, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto. In various aspects: a data processor gates the signal to provide a range-responsive measurement; the light signal is multiplexed; a circle-to-line interferometer optic transforms an at least partially circular fringe pattern to a substantially linear fringe pattern; or a CCD detector provides for recording a range-resolved image by successively transferring charges from one adjacent row of photosites to another.

Abstract: An accelerometer based on an optical displacement sensor is disclosed. An embodiment of the present invention directs a light beam toward an optically resonant cavity and detects both the reflected and transmitted optical beams that result from interaction with the optically resonant cavity. The optically resonant cavity has a cavity length that is based on the position of a proof mass that moves in response to an acceleration.

Abstract: In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.

Abstract: In determining an endpoint of etching a substrate, light that is directed toward the substrate is reflected from the substrate. A wavelength of the light is selected to locally maximize the intensity of the reflected light at an initial time point of the etching process. The reflected light is detected to determine an endpoint of the substrate etching process.

Abstract: A low cost spectral camera may include a multiple Fabry-Perot cavity filter with silicon photodetectors distributed one beside another in a two-dimensional matrix fashion. Each cavity may be designed to capture a pixel from an image. The two-dimensional fabry-perot array may function as a sensor to capture an image in spectral form. Spectral information may be obtained to generate spectral displays.

Abstract: A tunable optical band-pass device for spectrally filtering an input light beam is provided. The device includes an interferometer having two inner reflective planar surfaces that face each other and are tilted at an angle ? with respect to each other, and a translation device for adjusting a relative spacing of the two reflective surfaces, thus tuning the device to any arbitrary wavelength within a broad tuning range. The device also includes an input port for inputting the input light beam in the interferometer and having the input light beam impinge on one of the reflective surfaces at an incidence angle ? with respect thereto which is substantially larger than the tilt angle ?, and be partially reflected and partially transmitted by this surface thereby producing multiple transmitted light beams. An optical element for collecting the multiple transmitted light beams and producing a spectrally-filtered output light beam is also included.

Abstract: At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by an interferometer, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto. A data processor determines at least one air data product responsive thereto.

Abstract: An apparatus is provided for measuring a gas within a semiconductor thin film process. The apparatus includes an optical resonator disposed within an environment of the thin-film process, a tunable laser that excites the optical resonator at a characteristic frequency of the gas and a detector that detects an energy within the resonator.

Abstract: Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.

Abstract: An optical displacement sensor is disclosed that provides a optical displacement sensor that includes a optically-resonant cavity tuned to an operating wavelength without some of the disadvantages for doing so in the prior art. An embodiment of the present invention tunes an operating wavelength used with a Fabry-Perot interferometer to develop a desired relationship between the wavelength and the Fabry-Perot interferometer's initial cavity length.

Abstract: Raman systems include a radiation source, a radiation detector, and a Raman device or signal-enhancing structure. Raman devices include a tunable resonant cavity and a Raman signal-enhancing structure coupled to the cavity. The cavity includes a first reflective member, a second reflective member, and an electro-optic material disposed between the reflective members. The electro-optic material exhibits a refractive index that varies in response to an applied electrical field. Raman signal-enhancing structures include a substantially planar layer of Raman signal-enhancing material having a major surface, a support structure extending from the major surface, and a substantially planar member comprising a Raman signal-enhancing material disposed on an end of the support structure opposite the layer of Raman signal-enhancing material. The support structure separates at least a portion of the planar member from the layer of Raman signal-enhancing material by a selected distance of less than about fifty nanometers.

Abstract: Disclosed herein are methods and apparatus for testing interferometric modulators. The interferometric modulators may be tested by applying a time-varying voltage stimulus and measuring the resulting reflectivity from the modulators.

Abstract: A system and method for determining information about an assay. In one embodiment the method includes positioning a filter assembly, having an assay disposed on its surface, relative to a light source such that light from the light source is incident on the filter assembly and at least a portion of the light incident on the filter assembly is reflected from the filter assembly, illuminating the filter assembly with light from the light source, receiving light reflected from the filter assembly in an optical element, analyzing one or more characteristics of the light received in the optical element to determine information about a reaction in the assay, wherein a reaction in the assay results in a change of one or more characteristics of the light received from the filter assembly.

Abstract: An interferometer pressure sensor includes a reflective film configured to change a position thereof responsive to a pressure change and an interferometer element configured to detect the position change of the reflective film. A holder is configured to hold the reflective film and the interferometer element. The holder includes a first member formed of a first material having a first coefficient of thermal expansion and a second member formed of a second material having a second coefficient of thermal expansion that is different from the first coefficient of thermal expansion. The first member and the second member of the holder are sized and configured based on the first coefficient of thermal expansion and the second coefficient of thermal expansion so that a distance between the reflective film and the interferometer element is substantially constant over a temperature range.

Abstract: An optical displacement sensor is disclosed that provides a high signal-to-noise ratio output signal without some of the disadvantages for doing so in the prior art. An embodiment of the present invention directs a light beam toward a Fabry-Perot interferometer and detects both the reflected and transmitted optical beams that result from interaction with the Fabry-Perot interferometer. Signal processing techniques are applied to signals based on both the reflected and transmitted beams, resulting in higher signal strength and/or reduced noise in the resulting output signal.

Abstract: The invention relates to a device for remote measurement of the properties of the atmosphere, more particularly a device used to detect atmospheric turbulence. The device operates on the lidar principle, using the backscattering of a laser beam by the air. The device comprises a laser emission source (1), optical means (5) for collecting a backscattered beam (3) that is backscattered by targets illuminated by the emission source (1), the backscattered beam (3) being substantially centerd about the wavelength of the emission source (1), and means (9) for generating interference fringes (24) resulting from the backscattered beam (3). The device also includes a spatial filter (11) allowing only a central spot of the interference fringes to be seen and, at the center of the spatial filter (11), a mask for blocking off the center of the central spot and more particularly the Mie line of the backscattered beam.

Abstract: A method of and an input device for measuring scroll or click movement of an object and the input device relative to each other, includes determining the presence of the object on a window of the input device. Lower frequencies of an output signal from single sensor unit are separated and used for determining both the scroll and click motions. This allows measuring scroll movement and click movement with one sensor unit of the input device and reduction of costs and size of the input device.

Abstract: The invention aims to integrate a two-wave stationary interferometer on a photodetector during fabrication in order to constitute a miniature stationary Fourier transform spectrometer. The interferometer essentially comprises a plate having a first plane face coinciding with an image plane on semiconductor photosensitive elements and a second face that is not parallel to the first face. The second face reflects a wave that has a phase difference relative to the incident wave interfering with it that is a function of the local thickness of the plate.

Abstract: A resonant ellipsometer and method for determining ellipsometric parameters of a surface provide an efficient and low-cost mechanism for performing ellipsometric measurements. A surface of interest is included as a reflection point of a resonance optical path within a resonator. The intersection of the resonance optical path with the surface of interest is at an angle away from normal so that the complex reflectivity of the surface alters the phase of the resonance optical path. Intensity measurements of light emitted from a partially reflective surface of the resonator for orthogonal polarizations and for at least two effective cavity lengths provide complete information for computing the ellipsoidal parameters on the surface of interest. The resonator may be a Fabry-Perot resonator or a ring resonator. The wavelength of the illumination can be swept, or the cavity length mechanically or electronically altered to change the cavity length.

Abstract: Method and apparatus are disclosed that enable lasers to be stabilized in frequency to a high precision while simultaneously enabling rapid re-acquisition of stabilization control loops in the event of frequency locking loss. The principle of operation is to incorporate two etalons, one having a high finesse for frequency high stability, and one having a low finesse for wide error signal locking range, and electronics that pass control between two control systems in such a manner that any loss of frequency locking is rapidly re-acquired.

Abstract: A remote temperature sensing system includes a light source selectively producing light at two different wavelengths and a sensor device having an optical path length that varies as a function of temperature. The sensor receives light emitted by the light source and redirects the light along the optical path length. The system also includes a detector receiving redirected light from the sensor device and generating respective signals indicative of respective intensities of received redirected light corresponding to respective wavelengths of light emitted by the light source. The system also includes a processor processing the signals generated by the detector to calculate a temperature of the device.

Abstract: A tunable Fabry-Perot filter that is less sensitive to angle of incidence is formed by replacing the cavity (air gap) with a partitioned cavity that has an effective refractive index greater than one. The partitioned cavity includes a pair of partitioned cavity dielectric layers formed on the reflectors on either side of the variable air gap. Each of the dielectric layers has an optical thickness that is less than one fourth the shortest wavelength in the tuning range of the filter. The resulting three-layer partitioned cavity has an effective optical thickness substantially equal to an integral multiple (m) of one half the transmitted wavelength within the tuning range of the filter.

Abstract: A bandwidth meter apparatus and method for measuring the bandwidth of a spectrum of light emitted from a laser input to the bandwidth meter which may comprise an optical bandwidth monitor providing a first output representative of a first parameter which is indicative of the bandwidth or the light emitted from the laser and a second output representative of a second parameter which is indicative or the bandwidth of the light emitted from the laser; and, an actual bandwidth calculation apparatus utilizing the first output and the second output as part of a multivariable equation employing predetermined calibration variables specific to the optical bandwidth monitor, to calculate an actual bandwidth parameter; the multivariable equation comprising a symmetry sensitive term.

Abstract: A method and apparatus are disclosed for measuring a characteristic, e.g. spectral bandwidth, of a light beam. The apparatus may comprise an etalon for generating an interference pattern having at least one light cone, an arrangement of detector elements, the arrangement receiving a portion of the light cone and producing a signal indicative of the characteristic; and an auxiliary detector positioned to receive a portion of the light cone and produce a signal indicative of an alignment between the etalon and the linear arrangement.

Abstract: A chip-size wavelength detector includes a film with laterally varying transmission properties and a position-sensitive detector. The film transmits a different wavelength as a function of lateral position across the film. The position of a spot of light transmitted through the film will shift, depending on the wavelength of the light. The shift is measured by the position-sensitive detector.

Abstract: Wavelength-tunable radiation amplifying structures for Raman spectroscopy are disclosed that include resonant cavities having Raman signal-enhancing structures disposed therein. Systems that include the amplifying structures and methods of performing spectroscopic analysis using the structures and systems are also disclosed.

Abstract: An apparatus and method for detecting multiple beams from a beamsplitter is disclosed. Some embodiments of the present invention are particularly well-suited for use in microphones, high-sensitivity pressure sensors, vibration sensors, and accelerometer applications. Some embodiments of the present invention generate a differential electrical output signal that is based on multiple detected optical signals. The differential output signal is generated in response to an environmental stimulus, such as a pressure differential or incident acoustic energy. In accordance with the illustrative embodiment, an optical displacement sensor redirects the transmitted beam back through the optically-resonant cavity with an angular offset. Due to the angular offset, the redirected beam (i.e., retransmitted beam) transits the cavity with an intra-cavity path length that corresponds to substantially full transmittance of the retransmitted beam in the absence of the environmental stimulus.

Abstract: A bandwidth meter method and apparatus for measuring the bandwidth of a spectrum of light emitted from a laser input to the bandwidth meter is disclosed, which may comprise an optical bandwidth monitor providing a first output representative of a first parameter which is indicative of the bandwidth of the light emitted from the laser and a second output representative of a second parameter which is indicative of the bandwidth of the light emitted from the laser; and, an actual bandwidth calculation apparatus utilizing the first output and the second output as part of a multivarible equation employing predetermined calibration variables specific to the optical bandwidth monitor, to calculate an actual bandwidth parameter. The apparatus and method may be implemented in a laser lithography light source and/or in an integrated circuit lithography tool.

Abstract: The disclosure describes an absorption spectroscopy method for sensing hydrogen gas in a sample atmosphere and an associated hydrogen sensor. A light beam, having a wavelength corresponding to a vibrational transition of hydrogen molecules from a ground vibration state to any excited rotational vibration state via a quadrupole interaction, is introduced into an optical cavity adapted to receive a sample atmosphere to be tested for the presence of hydrogen gas. The light is introduced into the cavity in an off-axis alignment to systematically eliminate cavity resonances, while preserving the absorption signal amplifying properties of such cavities. Hydrogen absorption is measured is terms of cavity output, as in the ICOS technique.

Abstract: A contained resonant cavity. The contained resonant cavity includes a first surface and a second surface that are partially transmissive and partially reflective, One or more reflective sidewall, are positioned between the first surface and the second surface. In a specific embodiment, the first surface and the second surface are substantially parallel and represent input and output surfaces, respectively, of the contained resonant cavity. The one or more sidewalls are approximately perpendicular to the first surface and the second surface and include a first sidewall having a first substantially reflective planar surface that faces a second substantially reflective planar surface of the second sidewall. A third sidewall and a fourth sidewall have fourth and fifth substantially reflective Lacing sidewalls, respectively.

Abstract: An analyzer includes an optical tunable filter 1 for selectively outputting light having a predetermined wavelength, and a PD 421 for receiving light outputted from the optical tunable filter 1 and then passed through or reflected by an object to be measured.

Abstract: Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.

Abstract: An apparatus and method for controlling a laser system is disclosed which may comprise a spectrometer adapted to measure an unknown bandwidth of a spectrum of light emitted from the laser, which may comprise an optical bandwidth measuring unit adapted to provide as an output a measured parameter, which is indicative of a parameter of the unknown bandwidth of the spectrum being measured; a reported parameter computing unit adapted to compute a reported parameter of the unknown bandwidth of the spectrum being measured according to the formula: Reported Parameter(“RP”)=A*(Measured Parameter(“MP”))+C, wherein the RP and MP are a different type of parameter and the values of A and C are determined based upon calibration of the optical bandwidth measuring unit MP response for light of known valued of RP.

Abstract: Disclosed herein is a functional tunable multichannel filter which is capable of adjusting channel spacing and/or a wavelength location using polarization controllers (?/2, (?/4). The functional tunable multichannel filter includes one or more polarization maintaining fibers, a first polarization controller (?/2), a second polarization controller (?/4) and a 3 dB coupler. Additionally, the functional tunable multichannel filter is configured to tune a wavelength and adjust channel spacing by adjusting polarization of an optical signal passing through each of the polarization maintaining fibers using the first and second polarization controllers.

Abstract: An apparatus for measuring at least one parameter associated with a fluid flowing within a pipe comprises an optical measurement device and a signal processor. The optical measurement device provides output signals indicative of unsteady pressures within the fluid at two or more axial locations along the pipe in response to light reflected from an outer surface of the pipe. The signal processor provides an output signal indicative of at least one parameter associated with the fluid in response to the output signals. The optical measurement device may include, for example, an electronic speckle pattern interferometer, a Fabry-Perot device, and/or a laser vibrometer. The at least one parameter may include at least one of: density of the fluid, volumetric flow rate of the fluid, mass flow rate of the fluid, composition of the fluid, entrained air in the fluid, consistency of the fluid, size of particles in the fluid, and health of a device causing the unsteady pressures to be generated in the pipe.

Abstract: A method for calibrating a display device comprises controlling an applied voltage to at least one fabry-perot interferometer pixel through a plurality of switches. The at least one fabry-perot interferometer pixel has a top and a bottom plate defining a gap therebetween wherein the at least one fabry-perot interferometer pixel produces a selected output color in response to the applied voltage. The method further includes controlling a test voltage to the at least one fabry-perot interferometer pixel through the plurality of switches during a calibration sequence to determine a gap capacitance in the at least one fabry-perot interferometer. The gap capacitance represents the relative position of the top plate with respect to the bottom plate.

Abstract: Integrated spectroscopy systems are disclosed. In some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources. The tunable source combines one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon. The advantages associated with the use of the tunable etalon are that it can be small, relatively low power consumption device. For example, newer microelectrical mechanical system (MEMS) implementations of these devices make them the size of a chip. This increases their robustness and also their performance. In some examples, an isolator, amplifier, and/or reference system is further provided integrated.

Abstract: This invention relates to a measurement device, for optically measuring a property of a measurement object, the measurement device comprising a main resonator having a first and a second reflecting end defining a cavity having an effective optical cavity length, an optical gain element for generating light travelling along an optical beam path between the first and second reflecting ends, and a dispersive focusing resonator element which is positioned along the optical beam path between the optical gain element and the second reflecting end, whereby the measurement object is arranged to be at least partly positioned within the optical beam path of the main resonator, and whereby the measurement device further comprises a detection means for detecting a characteristic of light emitted from the main resonator, the value of the detected characteristic being a measure of a property of the measurement object.

Abstract: A fiber optic sensor system for pressure measurements where the design permits multiplexity on the input side of the system and the optical part of the system, which has a sensor Fabry-Perot interferometer and a read-out interferometer, is based on low coherence fiber-optic interferometry techniques. This permits a high dynamic range and low sensitivity to the wavelength fluctuation of the light source as well as to the optical intensity fluctuations. The system includes fiber tip based Fabry-Perot sensors, where each sensor includes a diaphragm as the transducer. A combined pressure gradient sensor, air particle velocity sensor, as well as acoustic intensity sensor is built based on the fiber tip based Fabry-Perot sensors.