Abstract: A method and apparatus for determining gas velocity, which includes generating transmitted radiation having an expected transmission frequency, detecting backscattered radiation, and determining gas velocity in dependence upon any Doppler shift of the frequency of the backscattered radiation, determining a transmission frequency of the transmitted radiation; detecting any difference between the measured transmission frequency and the expected transmission frequency and generating a feedback signal therefrom, and determining gas velocity using said feedback signal.

Abstract: Apparatuses and methods determine positional information from a reflected optical signal for an object on a per pixel basis. A spread spectrum imaging system includes a transmitting module transmitting a transmitted optical signal that illuminates a target space and contains a transmitted pulse that is modulated with a first pseudo-noise (PN) code. The imaging system includes a receiving module that receives a reflected optical signal from an object. The reflected signal is processed by an optical array that detects a detected signal from the reflected optical signal, where the detected signal contains a plurality of pixels spanning a target space. When the determined PN code corresponds to the selected PN code, image information and the positional information is presented for the object. When different positional information is obtained for different pixels in the image, the imaging system may determine that different objects appear in the received image.

Abstract: A method and apparatus are provided for sensing the mass flow rate of a fluid flowing through a pipe. A light beam containing plural individual wavelengths is projected from one side of the pipe across the width of the pipe so as to pass through the fluid under test. Fiber optic couplers located at least two positions on the opposite side of the pipe are used to detect the light beam. A determination is then made of the relative strengths of the light beam for each wavelength at the at least two positions and based at least in part on these relative strengths, the mass flow rate of the fluid is determined.

Abstract: The subject of the present invention is a laser anemometry probe for optical homodyne detection of frequency offset by Doppler effect, comprising two devices (DERF1, DERF2) for transmitting/receiving beams in two different directions, avoiding duplicating a plurality of elements of a mono-axial laser anemometry probe.

Abstract: A Doppler velocimeter apparatus that may have a coherent light source for generating a beam of coherent light. A modulating subsystem may receive and modulate at least a first portion of the beam of coherent light to form a first beam portion, the first beam portion forming a frequency offset and being a modulated, coherent optical signal. An optical element may receive the first beam portion and direct the first beam portion at a subject, the first beam portion being reflected from the subject to form a reflected beam that has a frequency that is modified in relation to the motion of the subject. A processing subsystem may receive a second portion of the beam of coherent light, and also the reflected beam, and uses the second beam portion and the reflected beam to determine a Doppler shift of the reflected beam.

Abstract: According to the invention, the monitoring system comprises two laser anemometers and a selection logic device able to select, on the one hand, a value of the IAS air speed to be displayed on first display means and, on the other hand, another value of the IAS air speed to be displayed on second display means.

Abstract: The device (1) comprises means (M1, UC) for determining an optimal orientation of a sighting axis of the anemometer (2) and for deducing therefrom the orientations of the other sighting axes.

Abstract: A method and device for determining anemometric parameters of an aircraft. The device (1) comprises four laser anemometers (A1, A2, A3, A4) that are mounted in pairs (CA, CB) symmetrically on the aircraft and means (4, 5) for determining the angle of sideslip and the angle of incidence of the aircraft, using measurements taken by these laser anemometers (A1, A2, A3, A4).

Abstract: The general field of the invention is that of gyrolasers comprising at least one ring-shaped optical cavity comprising at least three mirrors, a solid state amplifying medium pumped by a laser diode whose optical emission power is determined by a current supply source, the cavity and the amplifying medium being such that two so-called contra-rotating optical modes propagate in opposite directions to each other within the said optical cavity, the gyrolaser being a class B gyrolaser, the gyrolaser also comprising means of measuring the difference in optical frequency existing between the two optical modes. The gyrolaser comprises means of measuring the total optical power circulating in the optical cavity and first means of control of the current delivered by the supply source in such a way as to maintain the total optical power substantially constant in a narrow spectral band centred on the relaxation frequency of the laser.

Abstract: A heterodyne laser having a first optical path for guiding excitation light and a second optical path for guiding measurement light. The heterodyne laser includes an optical probe body for optically coupling and structurally combining the first optical path and the second optical path, and includes a reflection mirror, a beam splitter, a focal lens and a ¼ wavelength plate. The excitation light from the first optical path is introduced through the reflection mirror, the beam splitter and the focal lens into a measurement object.

Abstract: Exemplary embodiments of apparatus, method and computer accessible medium can be provided which can facilitate a determination of at least one characteristic of a structure. For example, it is possible to use at least one first arrangement which can be structured to provide at least one first transmitted radiation along a first axis and at least one second transmitted radiation along a second axis. The first and second transmitted radiations can impact the structure and generate respective first and second returned radiation. The first and second axis can be provided at a predetermined angle with respect with one another which is greater than 0. Further, at least one second arrangement can be provided which can be configured to receive data associated with the first and second returned radiations, and determine at least one relative velocity between the structure and the first arrangement along the first and second axes.

Abstract: A system and method for measuring crosswinds includes using a laser to send a signal on a signal path, and receiving response signals backscattered off of aerosols or other materials in the atmosphere along the signal path. Wavefronts of the received responses are perturbated by thermal cell turbulence in the atmosphere that perturbs optical wavefront propagation. Signals backscattered by airborne aerosols at different distances from the laser in the wavefront imager arrive at different times at the wavefront imager. Thus the wavefront perturbations vary with range, and data on the perturbed wavefront may be collected by the wavefront imager. Crosswinds cause movements in the optical perturbations over time, as the thermal cell turbulence moves. By comparing wavefronts of signals sent at different times an amount of thermal cell displacement may be determined at a series of ranges away from the laser and the wavefront imager.

Abstract: An optical method and apparatus are described for the measurement of properties of a travel vehicle or a travel surface upon which the travel vehicle travels, which includes providing an incident light from a light source to the travel surface, collecting light reflected from the travel surface, determining a surface induced Doppler shift from the incident and collected light and determining at least one of a motion property of the travel vehicle and a surface property of the travel surface based on the determined surface induced Doppler shift.

Abstract: The measurement method of the displacement speed of a moving element with respect to a fixed element is performed by means of an optic measuring device comprising a first reference sensor and a plurality of distinct second measurement sensors substantially aligned along the axis of movement of the moving element. The measurement method comprises determination of estimated speeds by correlation of the signals supplied by the reference sensor and each of the measurement sensors, and calculation of a mean speed of said estimated speeds.

Abstract: A method and an arrangement are provided to determine the speed of the wind, which acts on a wind-blade of a wind-turbine. An optical-signal with a known frequency is sent from an optical-transmit-unit to a joint measurement volume. The optical-signal is scattered and reflected by atmospheric particles of the joint measurement volume. The optical signal is shifted in its frequency due to the Doppler-principle, too. The frequency-shifted optical signal is received by a receive-unit. The frequency-shifted optical signal is compared with the sent optical-signal to determine the wind-speed based on the shifted frequency, which is caused by the atmospheric particles.

Abstract: Various light emitting diode (LED) based measurement systems and methods are provided. One system includes one or more arrays of LEDs arranged along a flow path of a sample. The array(s) are configured to illuminate the sample as the sample moves along the flow path. The system also includes one or more detectors configured to detect light resulting from illumination of the sample by the array(s). One method includes illuminating a microsphere at different positions along a flow path of the microsphere. The method also includes detecting light resulting from the illumination to produce individual output signals corresponding to the illumination at the different positions. The method further includes combining the individual output signals to produce a single output signal having a signal-to-noise ratio that is greater than a signal-to-noise ratio of the individual output signals.

Abstract: The system and method relate to detection of objects that are submerged, or partially submerged (e.g. floating), relative to a water surface. One aspect of the invention emits LIDAR fan-beam pulses and analyzes return-pulse portions to determine water-surface orientations and derive submerged-object images corrected for refractive distortion. Another defines simulated images of submerged objects as seen through waves in a water surface, prepares an algorithm for applying a three-dimensional image of the water surface in refractive correction of LIDAR imaging through waves—and also models application of the algorithm to the images, and finally specifies the LIDAR-system optics. Yet another emits nearly horizontal pulses to illuminate small exposed objects at tens of kilometers, detects reflected portions and images successive such portions with a streak-tube subsystem. Still others make special provisions for airborne objects.

Abstract: A counting device includes a counting unit, period measuring unit, frequency distribution unit, representative value unit, and correction value unit. The counting unit counts signals input during an interval. The signals have a single frequency when the physical quantity is constant. The period measuring unit measures the period of a signal interval. The frequency distribution unit generates the frequency distribution of signal periods from the measurement result. The representative value unit calculates the representative value of the distribution of periods from the frequency distribution. The correction value unit obtains a total sum Ns of frequencies in a class not more than a first predetermined multiple of the representative value and a total sum Nw of frequencies in a class not less than a second predetermined multiple of the representative value from the frequency distribution, and corrects the count result on the basis of the frequencies Ns and Nw.

Abstract: The system and method relate to detection of objects that are submerged, or partially submerged (e.g. floating), relative to a water surface. One aspect of the invention emits LIDAR fan-beam pulses and analyzes return-pulse portions to determine water-surface orientations and derive submerged-object images corrected for refractive distortion. Another defines simulated images of submerged objects as seen through waves in a water surface, prepares an algorithm for applying a three-dimensional image of the water surface in refractive correction of LIDAR imaging through waves—and also models application of the algorithm to the images, and finally specifies the LIDAR-system optics. Yet another emits nearly horizontal pulses to illuminate small exposed objects at tens of kilometers, detects reflected portions and images successive such portions with a streak-tube subsystem. Still others make special provisions for airborne objects.

Abstract: A relatively low-cost sensor can accurately detect, identify and track rapidly moving objects such as missiles, rocket propelled grenades (RPGs), mortars, explosive-driven fragments, bullets, shells, sports projectiles (baseballs, golf balls, tennis balls, arrows, etc.), and other types of objects. Systems that would incorporate such a sensor include military devices such as Active Protection System (APS), warning sensor systems, counter-fire systems; commercial devices such as an accurate baseball strike zone monitor, tennis ball line monitors, and arrow speed and flight characteristics monitors. The optical sensing system detects, identifies and tracks rapidly moving objects. The system is designed to be low-cost, rugged, highly reliable, and have a low False Alarm Rate (FAR). The system can accurately record signals from rapidly moving targets and then process this information with sufficient time to send a firing signal or take other action as appropriate.

Abstract: Provided is a measuring apparatus that includes: a semiconductor laser device that emits a laser light beam to an object to be measured; a driving unit that provides a driving signal for modulation drive of the semiconductor laser device; a first detection unit that detects a first electrical signal that corresponds to the intensity of the laser light beam modulated due to the self-coupling effect, in a first half-cycle of the driving signal; a second detection unit that detects a second electrical signal that corresponds to the intensity of a second laser light beam modulated due to the self-coupling effect, in a second half-cycle of the driving signal being in an opposite phase of the first half-cycle; a calculation unit that calculates a difference between the first and second electrical signals; and a measuring unit that measures a change in the state of the object based on the calculated difference.

Abstract: A light wave radar apparatus includes a frequency deviation detecting unit 12 for detecting a frequency deviation fchirp of a light signal, and a weighted average processing unit 13 for determining a systematic error ?Voffset from the frequency deviation fchirp detected by the frequency deviation detecting unit 12, and subtracts the systematic error ?Voffset from a wind velocity VW calculated by a Doppler signal processing unit 11. As a result, the light wave radar apparatus can carry out a measurement of the wind velocity VW with a high degree of precision.

Abstract: A method of sensing movement or proximity of objects by optical reflection is provided. The method includes the steps of transmitting a train of optical pulses towards a destination, sensing optical pulses reflected from the destination, and sensing and evaluating movement or proximity characteristics of objects at the destination with reference to variation in pulse width between transmitted and reflected optical pulses.

Abstract: A Doppler velocimeter apparatus and method of forming same. In one implementation a coherent light source is used for generating a beam of coherent light. An optical fiber receives the beam of coherent light. The optical fiber has an output face that is generally flat, thus enabling a first portion of the beam of coherent light to be reflected back on the optical fiber and to form a frequency offset, while a second portion of the beam of coherent light exits the optical fiber. A mechanism is used to move the output face of the optical fiber in an oscillating fashion so that the first portion of coherent light reflected back on the optical fiber produces an oscillating waveform that forms a frequency offset. An optical element receives the second portion of light from the face of the optical fiber and transmits it to a subject, and then receives a reflected optical signal back from the subject.

Abstract: An optical flow sensor is presented that directly measures the translational component of the optical flow experienced by the sensor while it is on a moving platform. The translational optical flow is measured by using a gyro to measure the platform's angular rates and then incorporating these angular rates in the optical flow computations in a manner that bypasses lags in the optical flow sensor measurement. In one embodiment, individual “velocity report” optical flow measurements have their rotational component removed before these velocity reports are utilized in the remainder of the optical flow algorithm. In another embodiment, a movable window and shifting techniques are used to form a windowed image that has no rotational optical flow components. In another embodiment, an optical flow sensor is mounted on a gimbal and held to point in one direction even as the platform on which the optical flow sensor is mounted moves.

Abstract: Apparatus for determining the velocity and direction of a moving object, the apparatus comprising: a coherent light (L) source arranged to generate an incident beam (B) of coherent light; an optical imaging system arranged to receive light reflected from a moving object passing through the incident beam and to focus the reflected light into a magnified image of the moving image; a first optical mask (M) through which the magnified image is projected, the mask having a first region of alternating opaque and non-opaque areas having a first spacing and second region of alternating opaque and non-opaque areas having a second spacing different from the first spacing; a first light detector (D) arranged to receive the light signal transmitted through the optical mask, the light signal comprising a series of pulses, and to calculate the velocity and direction of the moving object as a function of the pulse frequency and the spacing of the opaque areas of the optical mask.

Abstract: A laser driver (4) causes a semiconductor laser (1) to operate such that a first oscillation period of monotonically increasing the oscillation wavelength and a second oscillation period of monotonically decreasing the oscillation wavelength alternately exist. A photodiode (2) converts laser light emitted from the semiconductor laser (1) and return light from a measurement target (12) into electrical signals. A counting unit (13) counts the number of interference waveform components obtained from an output signal from the photodiode (2) in each of the first oscillation period and the second oscillation period. A computing device (9) calculates the distance to the measurement target (12) and the velocity of the measurement target (12) from a shortest Lasing wavelength and a longest Lasing wavelength in a period during which the counting unit (13) counts the number of interference waveform components and the counting result obtained by the counting unit (13).

Abstract: A system of lasers and detectors to detect the presence of objects and determine their speed is disclosed. The system comprises of a pair of lasers and a pair of detectors focused through a single lens or a pair of lenses. An electronic board that accompanies the lasers and detectors is used to provide the logic and decision making mechanism. Data collected and processed by the system yields such information as whether an object is present, whether the object is stationary or is moving, and subsequent speed information. The described system is also capable of providing additional information concerning the characteristics of the moving object such as its profile and length, and indication of a traffic violation.

Abstract: The invention relates to an optical measurement device intended for determining a relative velocity vector {right arrow over (v)} of a carrier, such as an aircraft, with respect to a reference medium MILREF. The device includes an optical signal system EMIREC, delivering an optical signal Sinc that follows a direction called the line of sight LDV and is concentrated in a focusing zone ZOF, and means for displacing the focusing zone ZOF in the reference medium MILREF.

Abstract: An optical flow sensor is presented that directly measures the translational component of the optical flow experienced by the sensor while it is on a moving platform. A prior art method of measuring translational optical flow is to simply subtract angular rates as measured by a gyro form the optical flow measurements. However this method produces noisy translational optical flow measurements resulting from lags between the gyro measurement and the optical flow measurement. In the teachings herein, translational optical flow is measured by using a gyro to measure the platform's angular rates and then incorporating these angular rates in the optical flow computations in a manner that bypasses lags in the optical flow sensor measurement. In one embodiment, individual “velocity report” optical flow measurements have their rotational component removed before these velocity reports are utilized in the remainder of the optical flow algorithm.

Abstract: Optical Coherence Tomography (OCT) is a high-resolution, non-invasive technique to image subsurface tissue and tissue functions. A broadband light source illuminates an object and the reflected photons are processed using an interferometer, demodulated into inphase and quadrature components and then digitized. The captured data contains information about the velocity of the moving scatterers but current Doppler estimation algorithms have a limited velocity detection range. Using a two dimensional velocity estimation, Doppler OCT (DOCT) can be used for the detection of in vivo aortic blood flow rates of over 1 m/s peak velocity through an esophageal DOCT probe. Previous methods have used a transverse Kasai (TK) autocorrelation estimation to estimate the velocity which is good for slow velocities, such as in the microvasculature. By calculating the Kasai autocorrelation with a lag in the depth or axial direction, backscattered frequency information is obtained which yields high velocity rate information.

Abstract: A stand-alone speedometer directly measuring the translational speed of a moving body comprises a source emitting two spaced light beams which interfere each other, mirrors or beam splitters changing directions of propagation of light beams, and a detector measuring the phase difference of light beams. Compared with the phase difference when the speedometer is stationary, the detector measures a first-order change of phase differences, which indicates the motion speed.

Abstract: A Doppler velocimeter apparatus and method of forming same. In one implementation a coherent light source is used for generating a beam of coherent light. An optical fiber receives the beam of coherent light. The optical fiber has an output face that is generally flat, thus enabling a first portion of the beam of coherent light to be reflected back on the optical fiber and to form a frequency offset, while a second portion of the beam of coherent light exits the optical fiber. A mechanism is used to move the output face of the optical fiber in an oscillating fashion so that the first portion of coherent light reflected back on the optical fiber produces an oscillating waveform that forms a frequency offset. An optical element receives the second portion of light from the face of the optical fiber and transmits it to a subject, and then receives a reflected optical signal back from the subject.

Abstract: The present invention relates to a method and apparatus used to calculate at least one velocity component for a target within the region. The invention employs an energy source which is activated using an activation system in a cyclic pattern with a selected source frequency. A receiver is also employed in conjunction with a shielding system where this shielding system is configured to block the sensing of reflected energy from the target in a cyclic pattern with a selected receiver frequency. The invention operates through measuring a frequency change in the source frequency of the energy source signal when received by the receiver and determines a velocity component for a target based on a measured frequency change for a known direction of travel. The invention may also be extended to provide a two or three dimensional velocity vector through the addition of further energy sources.

Abstract: A physical quantity sensor has a semiconductor laser, a laser driver for providing, to the semiconductor laser, a driving electric current that is a waveform wherein the maximum portions and minimum portions of a triangle wave have been rounded; detecting means (a photodiode and a current-voltage converting amplifier) for detecting an electric signal that includes an interference waveform that is produced by the self-coupling effect between a laser beam that is emitted from the semiconductor laser and a return beam from a measurement object; and measuring means (a filter circuit, a counting device, and a calculating device) for calculating a physical quantity for the measurement object from interference waveform information.

Abstract: A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Abstract: A traveling system for mobile bodies includes a control device for controlling traveling operation of a first and a second mobile bodies based on detection information provided by a relative distance detecting device mounted on only one of the first and second mobile bodies for detecting a distance to the other of the first and second mobile bodies, a first distance detecting device for detecting a distance between the first mobile body and a first reference position, and a second distance detecting device for detecting a distance between the second mobile body and a second reference position.

Abstract: An optical encoder including a sensor module including a light emitting member, a light receiving member opposite to the light emitting member to receive the emitted light, and at least one boss extending in a first direction; a shade member located between the light emitting member and the light receiving member and having a shading pattern; a first support supporting the sensor module and including at least one recessed portion engaged with the boss, and a groove connected with the recessed portion and extending in a second direction, wherein the sensor module is attached to the first support by being moved in the second direction while the boss is guided by the groove, and wherein the recessed portion has a depth greater than the height of the boss, and a portion of the groove adjacent to the recessed portion has a depth less than the height of the boss.

Abstract: An apparatus for measuring a closing velocity of a vehicle door includes a housing, first and second sensors, and a processor. The first sensor is coupled to the housing, has a first detection field, and is configured to generate a first signal when the vehicle door passes through the first detection field. The second sensor is coupled to the housing, has a second detection field, and is configured to generate a second signal when the vehicle door passes through the second detection field. The processor is in operable communication with the first and second sensors and is configured to receive the first and second signals and measure a time period between the receiving of the first and second signals.

Abstract: An apparatus has an optical member having a boundary surface on which light is incident, the optical member being adapted to transmit light entering the boundary surface from one side and to reflect light entering the boundary surface from the other side; a light source that emits light toward the optical member and irradiates light outgoing from the optical member onto a moving body; a camera that photographs via the optical member an image of light reflected from a reflection marker provided on a surface of the moving body; and a computation portion that computes movement information for the moving body based on the image of the light reflected by the reflection marker and photographed by the camera. An outgoing angle of the light outgoing from the boundary surface substantially coincides with an incoming angle at which the light reflected by the reflection marker enters the boundary surface.

Abstract: A method and apparatus for carrying our seismic exploration which comprises generating a seismic event; applying the seismic event to the earth's surface; detecting a response to the event, using an interferometer, in which there is relative motion between the earth's surface and the interferometer, the detected response including P-waves and S-waves in the earth's surface; and analysing the detected response; and in which: the detecting step comprises monitoring and recording the response to the seismic event in the form of movements of particles at the earth's surface, from a position spaced from the earth's surface, the detecting step being carried out over a response period, the response period being a predetermined period of time after the seismic event; and the analysing step comprises analysing the movements of particles at the earth's surface in the recorded response to the seismic event during the response period; the said relative motion having a total velocity Vtot which includes a transversal or t

Abstract: Apparatus and method for monitoring vibration levels in rotatable machinery (52). In one embodiment, a system (50) includes a source (66) for generating coherent radiation (70) and a first partially transmissive, partially reflective device (90) positioned to receive radiation (70) from the source (66) and transmit a part of the radiation there through. A second partially transmissive, partially reflective device (100) is mounted to the machinery (52), positioned to reflect a first signal (72) and transmit radiation (70) transmitted by the first device (90). A third device 104) is mounted to the machinery (52) and positioned to reflect radiation transmitted through the second device to provide a second signal (78).

Abstract: An image forming apparatus which can form an even image while maintaining high resolution. A speckle pattern detecting unit detects a speckle pattern on a surface of a photosensitive drum. A motor drive circuit controls the rotational speed of the photosensitive drum based on the detected speckle pattern on the surface of the photosensitive drum detected by the speckle pattern detecting unit.

Abstract: A device for measuring air turbulence in the surroundings of an aircraft includes a measurement system having lidars which are mounted on the aircraft and which are intended to carry out, during a flight of the aircraft, twelve measurements of aerodynamic velocity in the environment surrounding the aircraft. The measurement system carries out the twelve measurements at four different measurement points, each time according to three predetermined axes. A central unit which, with the aid of the aerodynamic velocity measurements and of a first order predetermined mathematical model describing an aerodynamic velocity field as a function of twelve variables, determines an aerodynamic velocity field which exists in the environment of the aircraft and which is representative of the air turbulence.

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: 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: A coherent Doppler lidar which can oscillate high energy pulses and output laser beams in a longer wavelength range of 1.5 ?m to the atmosphere is provided. The coherent Doppler lidar has a pulse laser an oscillation wavelength of which is controlled by means of injection locking of a seed light output from a master laser, wherein the pulse laser is a type in which a laser medium is disposed in a resonator, a pulse light of a predetermined repetition frequency is input to the laser medium as an excitation light, whereby pulse laser oscillation is generated in the resonator to output pulse laser beams from the resonator, and the laser medium being a type which has at least a region having Tm, Ho:YAG ceramics, and is excited by the excitation light to output pulse laser beams in 2 ?m wavelength band.

Abstract: In this multi-beam optical range sensor, since the diffraction grating splits output light of the light-emitting element into a plurality of beams, a plurality of beams can be outputted from the diffraction grating even with one light-emitting element. Therefore, according to this multi-beam optical range sensor, the numbers of the light-emitting elements and the light-emission side lenses can be cut down, the space on the light emission side can be reduced, and the sensor can be downsized. Also according to this range sensor, there is no need for scanning a plurality of light-emitting elements and so the detection time can be shortened.

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 plurality of transversely separated light collectors collected the scattered light; at least two telescopes are associated with a common second beam of light; or the telescope is coupled to a gimble mount that provides for positioning a region of overlap of the second beam of light with the field of view of the telescope.