Experience from the ultrasonic inspection of nuclear power plants has shown that large focused transducers are relatively effective in suppressing material structure noise. Operation of a large focused transducer can be thought of as integration (coherent summation) of individual beams reflected from the flaw and received by individual points at the transducer surface. Synthetic aperture focusi...

me time reversal process is applied to focus pulsed ultrasonic waves through the human skull bone. The aim is here whether to treat brain tumors, which are difficult to reach with classical surgery means, or to achieve ultrasonic imaging of the brain. Such medical applications require precise control of the size and location of the ultrasonic focal beam. But, the severe ultrasonic attenuation i...

Focusing light inside highly scattering media is a challenging task in biomedical optical imaging, manipulation, and therapy. A recent invention has overcome this challenge by time reversing ultrasonically encoded diffuse light to an ultrasound-modulated volume inside a turbid medium. In this technique, a photorefractive (PR) crystal or polymer can be used as the phase conjugate mirror for opti...

The application of laser ultrasonic technique is developed for evaluation of friction stir spot welding (FSSW) quality. The features of laser-generated ultrasonic waves in good welding and incomplete fusion area are simulated by finite element method (FEM). The non-contact laser ultrasonic inspection system (LUIS) was established to verify the numerical results. The interaction of laser ultraso...

Thermal ablation induced by high intensity focused ultrasound has produced promising clinical results to treat hepatocarcinoma and other liver tumors. However skin burns have been reported due to the high absorption of ultrasonic energy by the ribs. This study proposes a method to produce an acoustic field focusing on a chosen target while sparing the ribs using the decomposition of the time-re...