A real-time 32-element synthetic aperture acoustic imaging system has been developed. We can test new ideas for the system by using an acoustic array and carrying out image reconstruction on a computer. Contour plots of simple images are shown to illustrate the resolution (0.4 0.5 mm in range and transverse resolution) and sidelobe levels obtained with this synthetic-aperture technique. Rayleig...

Contrast-enhanced ultrasound has shown significant promise as a molecular imaging modality. However, one potential drawback is the difficulty that ultrasound contrast agents (UCA) may have in achieving adhesion to target molecules on the vascular endothelium. Microbubble UCA exhibit a lateral migration toward the vessel axis in laminar flow, preventing UCA contact with the endothelium. In the c...

The authors present a method based on dynamic force microscopy to characterize subnanometer-scale mechanical vibrations in resonant microand nanoelectromechanical systems. The method simultaneously employs the first eigenmode of the microscope cantilever for topography imaging and the second eigenmode for the detection of the resonator vibration. Here, they apply this scheme for the characteriz...

In this Letter, we report on the design and experimental characterization of a broadband acoustic hyperbolic metamaterial. The proposed metamaterial consists of multiple arrays of clamped thin plates facing the y direction and is shown to yield opposite signs of effective density in the x and y directions below a certain cutoff frequency, therefore, yielding a hyperbolic dispersion. Partial foc...

The miniaturization and three dimensional die stacking in advanced microelectronic packages poses a big challenge to their non-destructive evaluation by acoustic micro imaging. In particular, their complicated structures and multiple interfaces make the interpretation of acoustic data even more difficult. A common phenomenon observed in acoustic micro imaging of microelectronic packages is the ...

In this study, we demonstrate an acoustic system for high-resolution imaging of objects buried in soil. Our goal is to image cultural artifacts in order to assess in a rapid manner the historical significance of a potential construction site. We describe the imaging system and present preliminary images produced from data collected from a soil phantom. A mathematical model and associated comput...

In photo-acoustic imaging, energy absorption causes thermo-elastic expansion of optical absorbers, which in turn leads to propagation of a pressure wave. Recently, we have developed an efficient method for locating small absorbing regions inside a bounded domain from boundary measurements of the induced pressure wave and reconstructing the absorbed density. However, it is the absorption coeffic...

BACKGROUND Liquid core nanodroplets containing condensed gaseous fluorocarbons can be vaporized at clinically relevant acoustic energies and have been hypothesized as an alternative ultrasound contrast agent instead of gas-core agents. The potential for targeted activation and imaging of these agents was tested with droplets formulated from liquid octafluoropropane (C3) and 1:1 mixtures of C3 w...

Planar sensor arrays have advantages when used for photoacoustic imaging: they do not require the imaging target to be enclosed, and they are easier to manufacture than curved arrays. However, planar arrays have a limited view of the acoustic field due to their finite size; therefore, not all of the acoustic waves emitted from a photoacoustic source can be recorded. This loss of data results in...

........................................................................................................................................... ii Acknowledgements ......................................................................................................................... iii Chapter 1 Introduction ...........................................................................................