Abstract: A system for determining parameters of a cloud atmosphere within a wind tunnel. The system includes: a light projector configured to project a pulse of light energy into a projection field of view; at least one light detector having a detection field of view that forms a range-limited intersection with the projection field of view, the range-limited intersection having a maximum sampling range so as to exclude wall structures of the wind tunnel, wherein the at least one light detector is configured to detect a backscattered portion of the projected pulse of light energy backscattered from within the range-limited intersection; and a cloud parameter calculator configured to determine parameters of the cloud atmosphere based on the backscattered portions detected.

Abstract: Apparatus and associated methods relate to determining an effective size, quantity, shape, and type of water particles in a cloud atmosphere based on differences in amplitudes of optical signals backscattered at different backscattering angles. Off-axis backscattering—backscattering at angles other than 180 degrees—is affected by the effective size, quantity, shape, and type of water droplets. Detected amplitudes of optical signals that are backscattered at different angles are used to indicate the effective size, quantity, shape, and type of water particles in the cloud atmosphere. In some embodiments, optical emitters and detectors are configured to measure amplitudes of optical signals backscattered at backscattering angles of both on-axis—180 degrees—and off-axis varieties.

Abstract: Provided is an imaging device including a body, an x-ray detector assembly attached to the body, and an x-ray source assembly attached to the body. The x-ray detector assembly includes a telescopic actuator movable between a retracted position and an extended position, and an x-ray detector attached to the telescopic actuator.

Abstract: An aircraft ice detection system is configured to determine a condition of a cloud and includes a radar transmitter, a radar receiver, optics and a splitter. The radar transmitter is configured to produce quasi-optical radiation. The optics are configured to direct the quasi-optical radiation from the radar transmitter to the cloud and receive reflected quasi-optical radiation from the cloud. The radar receiver is configured to receive the reflected quasi-optical radiation from the optics and the splitter is configured to direct the reflected quasi-optical radiation from the optics to the radar receiver.

Abstract: Provided is an imaging device including a body, an x-ray detector assembly attached to the body, and an x-ray source assembly attached to the body. The x-ray detector assembly includes a telescopic actuator movable between a retracted position and an extended position, and an x-ray detector attached to the telescopic actuator.

Abstract: An aircraft ice detection system is configured to determine a condition of a cloud and includes a radar system, a lidar system, optics and a dichroic filter. The radar system is configured to project quasi-optical radiation to the cloud and receive reflected quasi-optical radiation from the cloud. The lidar system is configured to project optical radiation to the cloud and receive reflected optical radiation from the cloud. The optics are configured to direct the quasi-optical radiation and the optical radiation to the cloud and receive the reflected quasi-optical radiation and the reflected optical radiation from the cloud. The dichroic filter is configured to direct the quasi-optical radiation from the radar system to the optics, direct the optical radiation from the lidar system to the optics, direct the reflected quasi-optical radiation from the optics to the radar system and direct the reflected optical radiation from the optics to the lidar system.

Abstract: Apparatus and associated methods relate to reliably determining both size of large water droplets and density of small water droplets in a multi-modal cloud atmosphere. A pulsed beam of light is projected into the cloud atmosphere and a receiver receives a reflected portion of the projected pulsed beam backscattered by the cloud atmosphere. The received reflected portion is split into first and second parts. First and second parts are directed to first and second detectors, each having a different gain. A ratio of the gains of the first and second detector is greater than 3:1, thereby providing a low-gain detector for producing unsaturated signals indicative of scintillation spike reflection by large water particles and a simultaneous high-gain detector for producing signals indicative of range-resolved reflections by numerous small water particles.

Abstract: An aircraft system is configured to detect conditions of a cloud. The aircraft system includes a laser emitter, a fluorescent filter, optics, and an imager. The laser emitter generates a short pulse laser beam. The fluorescent filter is configured to convert the short pulse laser beam into a short pulse light beam such that the spectral content of the short pulse light beam is greater than the spectral content of the short pulse laser beam. The optics are configured to direct the short pulse light beam through a window of the aircraft into the cloud. The imager is configured to receive a reflected portion of the short pulse light beam from the cloud, and process the images to detect the cloud particles of interest.

Abstract: Apparatus and associated methods relate to reliably determining both size of large water droplets and density of small water droplets in a multi-modal cloud atmosphere. A pulsed beam of light is projected into the cloud atmosphere and a receiver receives a reflected portion of the projected pulsed beam backscattered by the cloud atmosphere. The received reflected portion is split into first and second parts. First and second parts are directed to first and second detectors, each having a different gain. A ratio of the gains of the first and second detector is greater than 3:1, thereby providing a low-gain detector for producing unsaturated signals indicative of scintillation spike reflection by large water particles and a simultaneous high-gain detector for producing signals indicative of range-resolved reflections by numerous small water particles.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by simultaneously projecting both a collimated pulsed beam into a narrow-field projection volume and a divergent pulsed beam into a wide-field projection volume of the cloud atmosphere, and then detecting both the collimated and divergent pulsed beams backscattered from within a detection volume of the cloud atmosphere. Projection and detection are configured such that the detection volume intersects both the narrow-field and the wide-field projection volumes defining narrow-field/detection and wide-field/reception detection volumes, respectively.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by simultaneously projecting both a collimated pulsed beam into a narrow-field projection volume and a divergent pulsed beam into a wide-field projection volume of the cloud atmosphere, and then detecting both the collimated and divergent pulsed beams backscattered from within a detection volume of the cloud atmosphere. Projection and detection are configured such that the detection volume intersects both the narrow-field and the wide-field projection volumes defining narrow-field/detection and wide-field/reception detection volumes, respectively.

Abstract: Apparatus and associated methods relate to a system for interfacing with an optically-powered sensor. The system includes an optical emitter configured to emit a beam of optical energy so as to provide operating power for the optically-powered sensor. The system includes an optical detector configured to detect a time sequence of optical pulses generated by the optically-powered sensor, the time sequence of pulses modulated between first and second optical power levels. The system includes a parameter extractor configured to determine a value of a sensed parameter based on the time sequence of optical pulses detected by the optical detector. The system also includes a power controller configured to control power level of the emitted beam of optical energy based on the first and/or second optical power levels detected by the optical detector.

Abstract: Apparatus and associated methods relate to determining, based on a detected portion of a projected pulse of quasi-optical energy backscattered by water particles within a divergent projection volume of a cloud atmosphere, properties of the backscattering water particles. The pulse of quasi-optical energy is projected into the divergent projection volume of the cloud atmosphere. The divergent projection volume is defined by an axis of projection and an angle of projection about the axis of projection. The portion of the projected pulse of optical energy backscattered by water particles within the divergent projection volume of the cloud atmosphere is received and detected. Various properties of the backscattering water particles, which can be determined from the detected portion of the projected pulse backscattered by water particles can include particle density and/or particle size.

Abstract: Apparatus and associated methods relate to a system for interfacing with an optically-powered sensor. The system includes an optical emitter configured to emit a beam of optical energy so as to provide operating power for the optically-powered sensor. The system includes an optical detector configured to detect a time sequence of optical pulses generated by the optically-powered sensor, the time sequence of pulses modulated between first and second optical power levels. The system includes a parameter extractor configured to determine a value of a sensed parameter based on the time sequence of optical pulses detected by the optical detector. The system also includes a power controller configured to control power level of the emitted beam of optical energy based on the first and/or second optical power levels detected by the optical detector.

Abstract: A system and method for detecting hard targets in a free-space laser system includes a laser, an optical detector, and electronics. The laser is configured to emit a laser beam along an optical path through transmitter optics into a field of view. The optical detector is positioned along a laser transmitter path and configured to receive retroreflections of the laser beam. The electronics are configured to determine if an output of the optical detector is indicative of presence of a hard target within the field of view, and control the laser to a safe state if the output is indicative of presence of the hard target.

Abstract: A system and method for detecting hard targets in a free-space laser system includes a laser, an optical detector, and electronics. The laser is configured to emit a laser beam along an optical path through transmitter optics into a field of view. The optical detector is positioned along a laser transmitter path and configured to receive retroreflections of the laser beam. The electronics are configured to determine if an output of the optical detector is indicative of presence of a hard target within the field of view, and control the laser to a safe state if the output is indicative of presence of the hard target.

Abstract: Apparatus and associated methods relate to determining sizes of water particles in a cloud atmosphere based on a detected portion of signals generated from a single monochromatic source and backscattered by water particles in a cloud atmosphere. A backscatter coefficient and an optical extinction coefficient are calculated, based on the detected portion of signals generated from the monochromatic source and backscattered by water particles in the cloud atmosphere. A LIDAR ratio—a ratio of the optical extinction coefficient to the backscatter coefficient, is calculated. Sizes of water particles in the cloud atmosphere are estimated based on the LIDAR ratio. An output signal indicative of the estimated sizes of water particles in the cloud atmosphere is generated. Estimating sizes of water particles using signals from a single monochromatic source advantageously can alert a pilot of an aircraft of cloud conditions, without requiring multi-chromatic sources.

Abstract: Apparatus and associated methods relate to determining a size and/or density of Super-cooled Large Droplets (SLDs) in a cloud atmosphere by comparing detected optical signals reflected from small and large sampling volumes of a cloud atmosphere. In some embodiments, an optical pulse is generated and divergently projected from a first optical fiber. A collimating lens is aligned within the divergently projected optical pulse collimating a portion thereof. The collimated and uncollimated portions of the optical pulse are projected into the small and large sampling volumes of the cloud atmosphere, respectively. The ratio of the collimated to the uncollimated portions can be optically controlled. Signals corresponding to optical pulses having different collimated/uncollimated ratios are backscattered by the cloud atmosphere, detected and compared to one another.

Abstract: An aircraft system is configured to detect conditions of a cloud. The aircraft system includes a laser emitter, a fluorescent filter, optics, and an imager. The laser emitter generates a short pulse laser beam. The fluorescent filter is configured to convert the short pulse laser beam into a short pulse light beam such that the spectral content of the short pulse light beam is greater than the spectral content of the short pulse laser beam. The optics are configured to direct the short pulse light beam through a window of the aircraft into the cloud. The imager is configured to receive a reflected portion of the short pulse light beam from the cloud, and process the images to detect the cloud particles of interest.

Abstract: Apparatus and associated methods relate to determining metrics of water particles in clouds by directing light pulses at a cloud and measuring a peak, a post-peak value and a high-frequency fluctuation of light signals reflected from the cloud. The light pulses include: a first pulse having circularly polarized light of a first wavelength; and a second pulse of a second wavelength. The reflected light signals include: a first reflected light signal having left-hand circular polarization of the first wavelength; a second reflected light signal having right-hand circular polarization of the first wavelength; and a third reflected light signal of the second wavelength. An extinction coefficient and a backscatter coefficient are determined based on the measured peak and post-peak slopes of the first and second reflected light signals. The measured high-frequency fluctuations of the three reflected light signals can be used to calculate cloud particle sizes.