Light focusing plays a central role in biomedical imaging, manipulation, and therapy. In scattering media, direct light focusing becomes infeasible beyond one transport mean free path. All previous methods1-3 to overcome this diffusion limit lack a practical internal "guide star."4 Here we proposed and experimentally validated a novel concept, called Time-Reversed Ultrasonically Encoded (TRUE) ...

In turbid media such as biological tissue, multiple scattering hinders direct light focusing at depths beyond one transport mean free path. As a solution to this problem, time-reversed ultrasonically encoded (TRUE) optical focusing is proposed based on ultrasonic encoding of diffused laser light and optical time reversal. In TRUE focusing, a laser beam of long coherence length illuminates a tur...

Time reversal is a very powerful method for focusing through complex and heterogeneous media and shows very promising results in biomedical applications. In this paper, we review some of the main applications investigated during the past decade. An iterative implementation of the time-reversal process allows tracking gallstones in real time during lithotripsy treatments. In this application dom...

Acoustic metalenses have been pursued over the past decades due to their pivotal role in a wide variety of applications. Recent research efforts demonstrated that, at ultrasonic regimes, acoustic levitation can be realized with standing waves, which are created by interference between incoming and reflected focused waves. However, conventional gradient-metasurface approach focus waves is comple...

Focusing an ultrasonic surface or bulk wave to a point can maximise the amount of ultrasonic energy at a point and increase the sensitivity of a measurement. Using noncontact ultrasonic methods we focus an ultrasonic wave pulse on or in a sample. Focusing can be achieved by using a shaped source or by the surface profile of the sample itself. Experiments and modelling confirm the known result t...

PURPOSE This study aims to demonstrate, using human cadavers the feasibility of energy-based adaptive focusing of ultrasonic waves using magnetic resonance acoustic radiation force imaging (MR-ARFI) in the framework of non-invasive transcranial high intensity focused ultrasound (HIFU) therapy. METHODS Energy-based adaptive focusing techniques were recently proposed in order to achieve aberrat...

Synthetic aperture focusing technique (SAFT) has been used in non-destructive testing mainly in its simplest form that mimics acoustic lenses used for focusing ultrasonic beams at a point of a solid object or structure. This paper presents a review of SAFT algorithms applied for post-processing of ultrasonic data acquired in non-destructive inspection of metals. The performance of SAFT in terms...

The use of numerical and phased array techniques to focus guided waves and perform inspection of plates and pipes has not been widely used; it represents an interesting solution for defect detection and localization. In addition, imaging of ultrasonic guided wave results using color coded B-Scans is also considered a highly valuable tool for data interpretation. While commercial ultrasonic phas...

Abstract This paper describes a stacked thin-plate region for focusing the transmitted waves. The was designed to focus wave field in bulk medium by utilizing dispersion nature of Lamb first numerical calculation proved that an incident plane changes wavefront because different phase velocities plates with thicknesses, and resulting focused at target. Second, when delayed longitudinal applied e...