If you're looking for more technical details you'll find a link to the recently published paper titled, Dexterous manipulation of microparticles using Bessel-function acoustic pressure fields at the source.
The other two methods rely on specially shaped laser beams - instead of a beam whose intensity peaks at its centre and tails off gradually, the team is investigating two alternatives: solenoid beams and Bessel beams.
The intensity peaks within a solenoid beam are found in a spiral around the line of the beam itself, while a Bessel beam's intensity rises and falls in peaks and troughs at higher distances from the beam's line.