We usually only post news about our papers published in Q1 journals, but recently LIMU staff and PhD students S.A. Tsysar, P.B. Rosnitsky, S.A. Asfandiyarov, S.A. Petrosyan, V.A. Khokhlova and O.A. Sapozhnikov presented the first use of the acoustic holography method for phase correction of a unique multi-element HIFU array with a mosaic arrangement of elements in the Acoustical Physics publication.

In the paper, surface vibrations of a unique focused fully populated array with mosaic arrangement of elements, developed at LIMU and manufactured by Imasonic for our lab with the support of the Moscow State University development program, were studied using acoustic holography method.

An experimental investigation of the acoustic pressure distribution of the new array revealed an asymmetry of the focal region. Acoustic holography made it possible to discover the source of the problem, which was the deviation of the oscillation phases of individual elements from the desired distribution. In addition to the noted undesirable distortion of the shape of the focal area, phase deviation led to a noticeable decrease in the level of peak pressure values that could significantly influence the effects produced by the ultrasound field of such array.

Introduction of inverted phase deviations (i.e., signal delays) obtained from the hologram for each transmitting element made it possible to:

• correct the shape of the focal area and obtain desirable one
• increase the acoustic pressure level at the focus by 14% in linear mode (and, thus, much more in nonlinear HIFU mode)

Details are in the available text of the paper.