Abstract: A vehicle detection and classification sensor provides accurate 3D profiling and classification of highway vehicles for speeds up to 100 mph. A scanning time-of-flight laser rangefinder is used to measure the distance to the highway from a fixed point above the road surface and then measure the distance to the surfaces of any vehicle that is viewed by the sensor. A rotating polygon scans a beam laser into two beams projected across the road surface at a fixed angle between them. The beam is pulsed at a high repetition rate for determining vehicle speeds with a high accuracy and uses the calculated speed and consecutive range measurements as the vehicle moves past the sensor to develop a three-dimensional profile of the vehicle. An algorithm is applied to the three-dimensional profile for providing a vehicle-classification.

Abstract: A sensor using laser range imaging technology is adapted for determining a three-dimensional profile of a vehicle passing the sensor for use in Intelligent Vehicle Highway Systems. A continuously pulsed laser beam scanned across a detection area determines the presence of a vehicle. Range, angle and time date for a vehicle passing the sensor are collected and stored for use in determining its three-dimensional profile. Forward and backward beams are directed for scanning across the detection area. Pulsed energy is sent into the two divergent beams, which are received as reflective energy in a receiver. The receiver accepts reflections from the beams and provides inputs for purposes of determining time of flight, and for measuring the time interval between interceptions of the two divergent beams for a given vehicle. An encoder tracks the position of the mirror for providing angle data with associated range measurements.

Abstract: An Intelligent Vehicle Highway System (IVHS) sensor provides accurate information on real-time traffic conditions that can be used for incident detection, motorist advisories, and traffic management via signals, ramp meters, and the like. A diode-laser-based Vehicle Detector And Classifier (VDAC) measures the presence, speed, and three-dimensional profiles of vehicles passing beneath it within its multi-lane field-of-view coverage. The sensor uses pulsed laser range imaging technology adapted for determining the three-dimensional profile of the vehicle. The VDAC employs a rotating polygon mirror to scan a pulsed laser rangefinder across three lanes of a highway in order to measure the presence, speed, and height profiles of vehicles in all three lanes simultaneously. A receiver accepts reflections from beams transmitted from the sensor and provides inputs for determining time of flight, and a time interval between interceptions of the two divergent beams for the vehicle.

Abstract: A transversely pumped solid state laser includes: a solid state gain medium having thickness, width and longitudinal dimensions; means for forming a laser cavity with the medium for generating a laser beam along the longitudinal dimension; and a semiconductor laser pump source for directing a collimated pump beam to the medium along the width dimension transversely to the longitudinal dimension constrained toward the center of the medium and having a width which is substantially shorter than the longitudinal dimension of the medium for spacing the edges of the collimated beam away from the longitudinal ends of the medium to reduce thermomechanical distortion of the longitudinal ends of the medium and consequent distortion of the laser beam.

Abstract: A sensor using pulsed laser range imaging technology is adapted for determining a three-dimensional profile of a vehicle passing the sensor for use in Intelligent Vehicle Highway Systems. A continuously pulsed laser beam scanned across a detection area determines the presence of a vehicle. Range, angle and time date for a vehicle passing the sensor are collected and stored for use in determining its three-dimensional profile. Forward and backward beams are directed for scanning across the detection area. Pulsed energy is sent into the two divergent beams, which are received as reflective energy in a receiver. The receiver accepts reflections from the beams and provides inputs for purposes of determining time of flight, and for measuring the time interval between interceptions of the two divergent beams for a given vehicle. An encoder tracks the position of the mirror for providing angle data with associated range measurements.

Abstract: A three-color coherent light system includes a laser source for generating a laser beam in the 1000-1100 nm wavelength region; means, responsive to the laser source, for generating the second harmonic of the laser beam; an optical parametric oscillator for providing a signal beam and an idler beam; means for splitting the second harmonic of the laser beam into a first beam for providing a source of coherent green light and a second beam for pumping the optical parametric oscillator to produce the signal and idler beams; means for generating the second harmonic of the signal beam as a source of coherent blue light; and means for generating the second harmonic of the idler beam as a source of coherent red light.

Abstract: A laser range camera provides both imaging and range information using laser radar techniques. A laser transmitter having a fan shaped beam that creates a column shaped beam in a far field is scanned along a single axis within a defined field of view using an acoustical optical device. A staring focal array of multiple line receivers having a long narrow field of view by using a linear array of fiber optics receives reflected energy from the scanned scene and transfers the received information to an avalanche photo diode by bundling the linear array into a circular array for interfacing with the diode. The range and intensity of each pixel within a scene is measured using a CCD measurement system which communicates with the receiver through the electrical signals. Range is determined for each pixel of the scene using the exposure characteristics of a CCD with analog type time of flight measurements.

Abstract: An object sensor and method using pulsed laser range imaging technology is adapted for determining the velocity and three dimensional profile of a vehicle passing the sensor for classifying the type of vehicle for use in Intelligent Vehicle Highway Systems. A pair of scanned laser beams are provided by splitting a continuously pulsed laser beam from a transmitter and an optical receiver determines the presence of a vehicle in a predetermined zone such as a highway weigh station or toll booth. Range, angle and time data are collected and stored for use in determining the speed of the vehicle passing the sensor and its three dimensional profile. Forward and backward scanned beams are provided using alternate embodiments of a rotating mirror and using two transmitters/receivers in another embodiment. The pulsed energy is sent into the two divergent beams, which are received as reflective energy in a receiver.

Abstract: A helicopter hazardous ground object warning system has a horizontally rotating beam from a laser rangefinder which detects and measures the distance to ground objects which may present a hazard to a helicopter during hover, takeoff and landing. The rotating laser beam from the rangefinder is positioned on the fuselage of a helicopter to create a quasi-horizontal (planar) scan pattern parallel to the earth's surface. The maximum and minimum ranges which can be measured by the rangefinder to objects and to ground personnel are preset. The minimum range can be used for blanking range measurements as a function of angle from helicopter parts, such as landing skids or wheel structures. A pilot warning system for hazardous objects may include an audible or visual alarm which may include a screen positioning all objects relative to the helicopter rotors and an external audible personnel warning system alerting ground personnel in the hazardous zone.

Abstract: A dual-wavelength laser system with intracavity, sum-frequency mixing including a bifurcated resonant cavity having a first arm, a second arm and a common arm; a first laser element located in the first arm for providing a first input laser beam of a first wavelength; a second laser element located in the second arm for providing a second input laser beam of a second wavelength; a nonlinear-mixing element in the common arm; and a beam combining device for combining the first and second beams and submitting them to the nonlinear-mixing element for providing an output laser beam of a third wavelength whose energy is the sum of the energy of the input laser beams.

Abstract: The sensor includes a range finder having means for emitting a directional output of pulsed energy toward a fixed area, and includes a transmitter section which divides pulsed energy into divergent beams, which are then received as reflective energy in a receiver section. The receiver alternately selects between outputs of two detectors receiving reflections from the beam and provide inputs for purposes of determining time of flight, and for measuring the time interval between interceptions of the two divergent beams for a given object. The sensor also receives inputs indicating the time that each pulse is emitted and the selected outputs from the detector to indicate when returning energy is received from the corresponding pulse to determine the elapsed time between the two.

Abstract: An object sensor and method using pulsed laser range imaging technology is adapted for controlling an agricultural spraying system. A single laser sensor employs a continuously scanned pulsed laser transmitter and optical receiver to determine the presence or absence of foliage in predetermined spray zones to selectively control spraying only in those spray zones where foliage has been sensed. Range and distance data are also collected and stored in a microprocessor for use in determining the appropriate zones requiring spraying.

Abstract: A wavelength-tunable, injection-seeded, dispersion-compensated, dispersively-pumped solid state laser includes a lasing medium; a highly reflective mirror; an output coupler; at least one isosceles Brewster prism oriented to the minimum deviation angle between the medium and the mirror for directing light of different wavelengths along different paths; means for varying the angle of the highly reflective mirror relative to the light from at least one Brewster angle for selecting a predetermined laser operating wavelength; a dispersion compensation apparatus associated with the lasing medium; a laser injection seeding port disposed between the dispersion compensation apparatus and one of the mirror and coupler and including a reflective surface at an acute non-Brewster angle to the laser beam for introducing a seed input; a dispersion compensation apparatus associated with the laser medium including opposite chirality optical elements; the lasing medium including a pump surface disposed at an acute angle to th

Abstract: A prism gain module is placed in a resonator for generating or amplifying coherent light energy. The module has a first and second side each with a planar surface. The surfaces are partially coated with a reflective material. The first and second sides are angled so that a resonator beam path is formed within the module such that coherent light energy enters an uncoated surface on the first side of the module of Brewster's angle, reflects off of the reflective material on the second and first sides, and then exits the module through the second side with an exit angle also equal to Brewster's angle. The prism gain module provides pump position flexibility by permitting coherent light energy to pump the gain module from multiple sides so long as the coherent light energy is focused along the beam path.

Abstract: A tunable laser rangefinder having a wavelength tunable transmitter output and a wavelength tunable receiver that matches the transmitter wavelength. The transmitter provides laser energy output pulses that are reflected off a target and received by the receiver. The time between the transmitter pulse and the receiver pulse is determined and the range of the target is calculated. The transmitter and receiver frequencies are changed from pulse to pulse to provide good countermeasure immunity. In a preferred embodiment the rangefinder uses a solid state, reliable cobalt magnesium fluoride laser to provide laser energy in a region of the infrared spectrum which is eye safe and has good atmospheric transmission.

Abstract: A method and apparatus is presented whereby control of the frequency of pulses emitted by a resonant ring slave laser is forced to a single frequency defined by a seed laser through the control of the pathlength of the ring laser resonant path. By monitoring the time difference between turn on of a Q-switch within the laser resonant cavity and the time of occurrence of the output pulse of the slave laser, and effecting changes to the ring laser resonant path in a manner to minimize the measured time difference, the frequency of the output pulse from the slave laser is driven to a single frequency defined by the seed laser resonator.

Abstract: A laser apparatus and method is provided for easily converting between standing-wave and ring-cavity configurations, by providing an optical coupler and an end mirror which are movable between retro-reflective and fold-reflective conditions.