Development of new instrumentation and techniques for real-time spatial interferometry of geophysical processes

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0345935ScalesSupport from this grant will allow the Physical Acoustics Lab at the Colorado School of Mines to acquire an ultrafast (femtosecond) mode-locked laser, ultrafast CCD camera (100 ns shutter) based imaging spectrometer, and ancillary equipment necessary to dramatically improve the signal to noise ratio and acquisition speed of laser interferometric techniques for high fidelity spatial and temporal observations of the propagation of elastic waves across the surfaces of natural and man-made materials. In traditional seismic and ultrasonic measurements, contacting transducers are used to measure elastic waves at a single point. Under previous support from this program (EAR-0111804) Scales and his Ph.D. student (K. van Wijk), now a research scientist at CSM), developed a laser vibrometer interferometric technique for non-contact and non-destructive seismology which can measure elastic waves at tens of thousands of points. This support will facilitate more rapid non-contacting acoustic interferometric techniques and will therefore allow for improved spatial distribution of measurements over the surface of samples. While the technique will not allow for study of rock properties under in situ conditions, it will offer the opportunity to measuring the temporal evolution of elastic wavefields in highly scattering media. This grant is a leveraged investment in a unique technology that has potential broad implications for medical imaging, non-destructive evaluation, land-mine detection, hydrocarbon exploration and seismology. ***