Abstract: A method and a system for characterizing an elemental composition and a molecular composition of a material are provided. Laser-based IR spectroscopy measurements and LIBS measurements are performed at a same analysis spot on the material. The IR spectroscopy measurement data can be used to characterize the molecular composition of the material, whereas the LIBS data can be used to characterize the elemental composition of the material. 2D and 3D profiles of a sample of the material may be obtained based on this data.

Abstract: A technique for automated online inspection of manufacture of a fibre reinforced polymer composite part during automated ribbon placement (e.g. ATL or AFP) uses interferometric inspection (e.g. OCT) to detect deviations from a planned lay-up for the part, to identify defects. On line, real-time inspection (i.e. on-the-fly) is demonstrated, and edge type defects and whole surface defects are identifiable. A sensor is demonstrated that does not extend a working envelope of the robotic head used for rib bon placement.

Abstract: A method and a system for characterizing an elemental composition and a molecular composition of a material are provided. Laser-based IR spectroscopy measurements and LIBS measurements are performed at a same analysis spot on the material. The IR spectroscopy measurement data can be used to characterize the molecular composition of the material, whereas the LIBS data can be used to characterize the elemental composition of the material. 2D and 3D profiles of a sample of the material may be obtained based on this data.

Abstract: A method for laser induced breakdown spectroscopy (LIBS) calibration or LIBS assay comprises providing a plurality of reference samples, each having a respective, known concentration of an analyte, assaying each reference sample to obtain a respective LIBS spectrum, and for each reference LIBS spectrum, measuring an intensity of at least one spectral analyte line that varies with concentration of the analyte, and measuring a peak amplitude of at least one saturating line of a reference element. The ratio and known concentrations define a calibration curve for the analyte.

Abstract: A method and system for inspecting biological tissue that has no applied coatings or treatments to improve reflectivity comprises an optical detection system with an exposed surface for inspection by an optical detection system; and a laser for exciting an ultrasonic wave within the tissue, which wave propagates within the tissue at least near the surface.

Abstract: A technique for automated online inspection of manufacture of a fibre reinforced polymer composite part during automated ribbon placement (e.g. ATL or AFP) uses interferometric inspection (e.g. OCT) to detect deviations from a planned lay-up for the part, to identify defects. On line, real-time inspection (i.e. on-the-fly) is demonstrated, and edge type defects and whole surface defects are identifiable. A sensor is demonstrated that does not extend a working envelope of the robotic head used for rib bon placement.

Abstract: A method for laser induced breakdown spectroscopy (LIBS) calibration or LIBS assay comprises providing a plurality of reference samples, each having a respective, known concentration of an analyte, assaying each reference sample to obtain a respective LIBS spectrum, and for each reference LIBS spectrum, measuring an intensity of at least one spectral analyte line that varies with concentration of the analyte, and measuring a peak amplitude of at least one saturating line of a reference element. The ratio and known concentrations define a calibration curve for the analyte.

Abstract: A method and system for inspecting biological tissue that has no applied coatings or treatments to improve reflectivity comprises an optical detection system with an exposed surface for inspection by an optical detection system; and a laser for exciting an ultrasonic wave within the tissue, which wave propagates within the tissue at least near the surface.

Abstract: A technique for acoustic detection of a disbond within a bonded structure involves thermal excitation of the surface of the bonded structure to induce a lifting and membrane vibration and is applicable to laminates and coated structures, as well as foam core structures or a honeycomb structures. The technique does not require access to both sides of the bonded structure. A large etendue interferometer is used to provide surface displacement measurement. The surface displacement measurement can be analyzed both by frequency or amplitude to determine existence of a disbond by membrane vibration, and further a thickness of the disbond can be determined using traditional pulse-echo time analysis. The technique may allow detection of stick bonds.

Abstract: A technique for acoustic detection of a disbond within a bonded structure involves thermal excitation of the surface of the bonded structure to induce a lifting and membrane vibration and is applicable to laminates and coated structures, as well as foam core structures or a honeycomb structures. The technique does not require access to both sides of the bonded structure. A large etendue interferometer is used to provide surface displacement measurement. The surface displacement measurement can be analyzed both by frequency or amplitude to determine existence of a disbond by membrane vibration, and further a thickness of the disbond can be determined using traditional pulse-echo time analysis. The technique may allow detection of stick bonds.

Abstract: A method and system is disclosed for determining a property of an object by measuring ultrasonic attenuation. With the proposed method, a measured ultrasonic interaction signal of the object is compared with a reference signal produced using the same generation and detection setup, but using a reference part. The reference ultrasonic signal has low attenuation, and exhibits equivalent diffraction properties as the object, with respect to a broadband ultrasonic pulse. The difference is attributable to the attenuation of the object. The attenuation as a function of frequency, the attenuation spectrum, is fitted to a model to obtain a parameter useful for identifying one of the many properties of an object that varies with ultrasonic attenuation.

Abstract: A method and system is disclosed for determining a property of an object by measuring ultrasonic attenuation. With the proposed method, a measured ultrasonic interaction signal of the object is compared with a reference signal produced using the same generation and detection setup, but using a reference part. The reference ultrasonic signal has low attenuation, and exhibits equivalent diffraction properties as the object, with respect to a broadband ultrasonic pulse. The difference is attributable to the attenuation of the object. The attenuation as a function of frequency, the attenuation spectrum, is fitted to a model to obtain a parameter useful for identifying one of the many properties of an object that varies with ultrasonic attenuation.

Abstract: Laser ablation combined with spectrometric analysis is a good tool for determining the composition of heterogeneous materials. By measuring the depth of an ablation crater at a target of a heterogeneous material, it is possible to generate a compositional profile as a function of the depth. It is also possible to generate a 3 dimensional profile by depth profiling of a plurality of craters. The depth measurement is conducted in situ and in real time so that the evolution of composition as a function of the depth can be measured. An interferometric technique with a short coherence length light is one of the preferred embodiments for measuring the depth in situ and in real time.

Abstract: In a method for ultrasonic testing of objects, ultrasound is generated inside or at the surface of the object. The surface of the object is illuminated with a beam from a long-pulse laser oscillator, typically in the range 1 &mgr;s to a few 100 &mgr;s, that is substantially free of intensity fluctuations. The light from the incident beam that is scattered or reflected by the surface of the object is collected and demodulated to obtain a signal representative of the ultrasonic motion. The method allows for the use of a compact and efficient arrangement.

Abstract: In order to probe an object in motion subject to surface displacement, for example, caused by ultrasonic wave propagation, a laser beam is split into a first portion and a second portion. The first is scatted off the object to generate a signal beam. The frequency shift produced in the signal beam due to motion of the object is measured, and this is used to adjust the frequency of one or both portions of the laser beam so that both beams have substantially the same frequency. The surface displacements are measured by comparing the second portion of the laser beam and the signal beam after frequency adjustment.

Abstract: Laser ablation combined with spectrometric analysis is a good tool for determining the composition of heterogeneous materials. By measuring the depth of an ablation crater at a target of a heterogeneous material, it is possible to generate a compositional profile as a function of the depth. It is also possible to generate a 3 dimensional profile by depth profiling of a plurality of craters. The depth measurement is conducted in situ and in real time so that the evolution of composition as a fucntion of the depth can be measured. An interferometric technique with a short coherence length light is one of the preferred embodiments for measuring the depth in situ and in real time.

Abstract: A method and an apparatus for non-contact and non-invasive characterization of a moving thin sheet and in particular of a paper web on a production line. The method uses a laser for the generation of sonic and ultrasonic waves in the thin sheet and a speckle insensitive interferometric device for the detection of these waves. The generation is performed in conditions to avoid damage impeding further use of the sheet. When the generation and detection spots overlap, the method provides a measurement of the compression modulus. When the generation and detection spots are separated by a known distance and plate waves (Lamb waves) are generated and detected, the method provides a measurement of the in-plane modulus and of the tension applied to the sheet. By detecting waves propagating in various directions, either by rotating the detection sensor head or multiplexing the signals provided by several detection or generation locations, the anisotropy of the in-plane modulus is determined.

Abstract: In order to probe an object in motion subject to surface displacement, for example, caused by ultrasonic wave propagation, a laser beam is split into a first portion and a second portion. The first is scatted off the object to generate a signal beam. The frequency shift produced in the signal beam due to motion of the object is measured, and this is used to adjust the frequency of one or both portions of the laser beam so that both beams have substantially the same frequency. The surface displacements are measured by comparing the second portion of the laser beam and the signal beam after frequency adjustment.

Abstract: A method and system is provided for enhanced ultrasonic detection and imaging of small defects inside or at the surface of an object. The Synthetic Aperture Focusing Technique (SAFT) has been used to improve the detectability and to enhance images in conventional ultrasonics and this method has recently been adapted to laser-ultrasonics. In the present invention, an improved version of the frequency-domain SAFT (F-SAFT) based on the angular spectrum approach is described. The method proposed includes temporal deconvolution of the waveform data to enhance both axial and lateral resolutions, control of the aperture and of the frequency bandwidth to improve signal-to-noise ratio, as well as spatial interpolation of the subsurface images. All the above operations are well adapted to the frequency domain calculations and embedded in the F-SAFT data processing. The aperture control and the spatial interpolation allow also a reduction of sampling requirements to further decrease both inspection and processing times.

Abstract: An apparatus and method for mapping out wall thickness of a tube or other object having motion in two directions. The device includes a first laser for generating ultrasound propagating inside tube wall over a particular generation spot on a surface of the tube, a second laser coupled to an interferometer for detecting produced ultrasonic echoes over a detection spot on the surface. A processor is provided for operating on recorded ultrasonic echoes and using a given value of ultrasonic velocity and the distance between the generation spot and the detection spots for determining wall thickness at a mid-point between the generation and detection spot. An optical displacement measuring device determines a displacement in two dimensions between the generation spot and arbitrary starting spot and a display for displaying wall thickness values over the surface of the tube.