Singular acoustics: Transfer of orbital angular momentum to matter

Abstract

A general feature of wave physics is the existence of phase singularities. One usually refers to beams carrying phase singularities as vortex beams, which have become more popular in the field of optics than in acoustics. In particular, the first experimental demonstration of transfer of orbital angular momentum of sound to matter came much later than its optical counterpart. Here, we will review our recent results regarding the transfer of acoustic orbital angular momentum to matter in the ultrasonic domain. This includes (i) the quantitative test of acoustic orbital angular momentum transfer to a sound absorbing object, (ii) the introduction of a novel phenomenon named “rotational acoustic streaming,” and (iii) the demonstration a nondissipative sound-matter orbital angular momentum transfer mediated by chiral scattering.