Abstract: Methods and systems for measuring one or more properties of a soft material employ air transmitted ultrasound that is reflected from the soft material to generate a mechanical wave in the soft material. A method of measuring one or more properties of a soft material includes transmitting ultrasound through air to an interface boundary between the soft material and air. Force is applied to the soft material by reflecting the ultrasound from the soft material. A mechanical wave is generated in the soft material as a result of the force applied to the soft material. Propagation of the mechanical wave in the soft material is measured with an imaging system. One or more properties of the soft material is determined based on the measured propagation of the mechanical wave in the soft material.

Abstract: A method for testing a structure using laser ultrasound includes steps of: (1) directing positioning light on a surface of the structure; (2) determining a spatial location and a spatial orientation of the surface from an evaluation of the positioning light reflected back from the surface; (3) directing pump light onto the surface to generate ultrasonic waves in the structure; (4) selectively locating a probe-light focal point of probe light on the surface, based on the spatial location determined for the surface; (5) selectively angularly orienting the probe light normal to the surface, based on the spatial orientation determined for the surface; and (6) directing the probe light onto the surface to detect a response to the ultrasonic waves.

Abstract: A non-contact photoacoustic spectrophotometry system is configured to measure an absorption spectrum of a material. The system includes a modulated light source such as tunable pulsed laser that generates laser pulses to produce photoacoustic signals in the material. A non-contact detector monitors the surface of the container for the material. The detector includes a second light source, such as a continuous wave laser, focused on the surface of the container, and transmits reflected light to an interferometer, for example, a Sagnac interferometer. The interferometer produces an interference signal from the received light that is proportional to the acoustic pressure, which is transmitted to a computer to calculate an absorption coefficient. Using a plurality of wavelengths from the tunable pulsed laser, an absorption spectrum may be generated.

Abstract: Methods and system for producing combined photoacoustic/ultrasonic image frames use a low-power narrow beam laser to direct sequential pulses along a path overlying an internal region of interest. Photoacoustic responses are received and used to generate sub-frames. Between each of the laser pulses a plurality of ultrasound pulse-echo beams are sequentially emitted towards the region of interest, and the reflections are received and used to generate ultrasound sub-frames. The photoacoustic sub-frames are combined to produce a photoacoustic frame, and the ultrasound sub-frames are combined to produce an ultrasound frame. The photoacoustic and ultrasound frames are combined to produce an image frame. The method and system are suitable for producing real-time, high-contrast video.

Abstract: Methods and systems for measuring one or more properties of a soft material employ air transmitted ultrasound that is reflected from the soft material to generate a mechanical wave in the soft material. A method of measuring one or more properties of a soft material includes transmitting ultrasound through air to an interface boundary between the soft material and air. Force is applied to the soft material by reflecting the ultrasound from the soft material. A mechanical wave is generated in the soft material as a result of the force applied to the soft material. Propagation of the mechanical wave in the soft material is measured with an imaging system. One or more properties of the soft material is determined based on the measured propagation of the mechanical wave in the soft material.

Abstract: A method for testing a structure using laser ultrasound includes steps of: (1) directing positioning light on a surface of the structure; (2) determining a spatial location and a spatial orientation of the surface from an evaluation of the positioning light reflected back from the surface; (3) directing pump light onto the surface to generate ultrasonic waves in the structure; (4) selectively locating a probe-light focal point of probe light on the surface, based on the spatial location determined for the surface; (5) selectively angularly orienting the probe light normal to the surface, based on the spatial orientation determined for the surface; and (6) directing the probe light onto the surface to detect a response to the ultrasonic waves.

Abstract: Systems and methods process a measured ultrasonic response waveform to determine a well casing thickness and an acoustic impedance of a sealing medium surrounding the well casing. An array of simulated response waveforms corresponding to a set of candidate acoustic impedances for the sealing medium surrounding the well casing and a set of candidate well casing thicknesses is generated. A simulated response waveform from the array of simulated response waveforms is identified that best matches the measured response waveform so as to determine the sealing medium acoustic impedance.

Abstract: A method of detecting local material changes in a composite structure is presented. A pulsed laser beam is directed towards the composite structure comprised of a number of composite materials. Wide-band ultrasonic signals are formed in the composite structure when radiation of the pulsed laser beam is absorbed by the composite structure. The wide-band ultrasonic signals are detected to form data. The data is processed to identify a local frequency value for the composite structure. The local frequency value is used to determine if local material changes are present in the number of composite materials.

Abstract: A non-contact photoacoustic spectrophotometry system is configured to measure an absorption spectrum of a material. The system includes a modulated light source such as tunable pulsed laser that generates laser pulses to produce photoacoustic signals in the material. A non-contact detector monitors the surface of the container for the material. The detector includes a second light source, such as a continuous wave laser, focused on the surface of the container, and transmits reflected light to an interferometer, for example, a Sagnac interferometer. The interferometer produces an interference signal from the received light that is proportional to the acoustic pressure, which is transmitted to a computer to calculate an absorption coefficient. Using a plurality of wavelengths from the tunable pulsed laser, an absorption spectrum may be generated.

Abstract: A method of detecting material changes in a composite structure is presented. A pulsed laser beam is directed towards the composite structure comprised of a number of composite materials. Wide-band ultrasonic signals are formed in the composite structure when radiation of the pulsed laser beam is absorbed by the composite structure. The wide-band ultrasonic signals are detected to form data. The data comprises a number of ultrasonic A-scans. The data is processed to identify a plurality of frequency measurements for each of the number of ultrasonic A-scans. A frequency image is displayed using the plurality of frequency measurements. The material changes are represented in the frequency image.

Abstract: A compact and portable apparatus for measuring properties of objects utilizing a fiber optic Sagnac interferometer is enabled. The fiber optic Sagnac interferometer may be a double differential Sagnac interferometer. The interferometer core may be implemented with fiber optic components including polarization maintaining optical fiber, and by utilizing an auto-balanced avalanche photodetector. An optical switch may be incorporated to maintain relatively low average probe signal power while allowing optimal peak probe signal power. The compact and portable apparatus may be configured to measure ultrasonic vibrations, a displacement of an object surface in response to ultrasonic vibrations, and/or a vibration speed of the object surface. A wideband light source may be amplified and stabilized. A sensor head of the interferometer may incorporate a collimator adjustable to block a central portion of the projected probe beam thereby at least in part enabling in-plane and out-of-plane measurements.

Abstract: Systems and methods process a measured ultrasonic response waveform to determine a well casing thickness and an acoustic impedance of a sealing medium surrounding the well casing. An array of simulated response waveforms corresponding to a set of candidate acoustic impedances for the sealing medium surrounding the well casing and a set of candidate well casing thicknesses is generated. A simulated response waveform from the array of simulated response waveforms is identified that best matches the measured response waveform so as to determine the sealing medium acoustic impedance.

Abstract: A method of detecting inconsistencies in a structure is presented. A pulsed laser beam is directed towards the structure. A plurality of types of ultrasonic signals is formed in the structure when radiation of the pulsed laser beam is absorbed by the structure. The plurality of types of ultrasonic signals is detected to form data.

Abstract: Systems and methods process a measured ultrasonic response waveform to determine a well casing thickness and an acoustic impedance of a sealing medium surrounding the well casing. An array of simulated response waveforms corresponding to a set of candidate acoustic impedances for the sealing medium surrounding the well casing and a set of candidate well casing thicknesses is generated. A simulated response waveform from the array of simulated response waveforms is identified that best matches the measured response waveform so as to determine the sealing medium acoustic impedance.

Abstract: A method of detecting inconsistencies in a structure is presented. A pulsed laser beam is directed towards the structure. A plurality of types of ultrasonic signals is formed in the structure when radiation of the pulsed laser beam is absorbed by the structure. The plurality of types of ultrasonic signals is detected to form data.

Abstract: A method of detecting material changes in a composite structure is presented. A pulsed laser beam is directed towards the composite structure comprised of a number of composite materials. Wide-band ultrasonic signals are formed in the composite structure when radiation of the pulsed laser beam is absorbed by the composite structure. The wide-band ultrasonic signals are detected to form data. The data comprises a number of ultrasonic A-scans. The data is processed to identify a plurality of frequency measurements for each of the number of ultrasonic A-scans. A frequency image is displayed using the plurality of frequency measurements. The material changes are represented in the frequency image.

Abstract: A method of detecting local material changes in a composite structure is presented. A pulsed laser beam is directed towards the composite structure comprised of a number of composite materials. Wide-band ultrasonic signals are formed in the composite structure when radiation of the pulsed laser beam is absorbed by the composite structure. The wide-band ultrasonic signals are detected to form data. The data is processed to identify a local frequency value for the composite structure. The local frequency value is used to determine if local material changes are present in the number of composite materials.

Abstract: A compact and portable apparatus for measuring properties of objects utilizing a fiber optic Sagnac interferometer is enabled. The fiber optic Sagnac interferometer may be a double differential Sagnac interferometer. The interferometer core may be implemented with fiber optic components including polarization maintaining optical fiber, and by utilizing an auto-balanced avalanche photodetector. An optical switch may be incorporated to maintain relatively low average probe signal power while allowing optimal peak probe signal power. The compact and portable apparatus may be configured to measure ultrasonic vibrations, a displacement of an object surface in response to ultrasonic vibrations, and/or a vibration speed of the object surface. A wideband light source may be amplified and stabilized. A sensor head of the interferometer may incorporate a collimator adjustable to block a central portion of the projected probe beam thereby at least in part enabling in-plane and out-of-plane measurements.

Abstract: A method and apparatus for testing a composite structure. A pulsed laser beam having a number of properties is generated. Each of the number of properties is within a selected range. The pulsed laser beam generated by the generation laser system is directed towards a composite structure comprised of a number of composite materials. A number of ultrasonic waves are formed in the composite structure when the pulsed laser beam contacts the composite structure without causing any undesired inconsistencies in the composite structure outside of selected tolerances.

Abstract: Systems and methods process a measured ultrasonic response waveform to determine a well casing thickness and an acoustic impedance of a sealing medium surrounding the well casing. An array of simulated response waveforms corresponding to a set of candidate acoustic impedances for the sealing medium surrounding the well casing and a set of candidate well casing thicknesses is generated. A simulated response waveform from the array of simulated response waveforms is identified that best matches the measured response waveform so as to determine the sealing medium acoustic impedance.