Optically induced ejection of particles or cells in acoustic levitation

Collaborators : Gabriel Dumy (PhD student between 2016 – 2019), Angelica Castro (Post-doc 2018-19)

We recently discovered that that the standard aggregation process of particles in acoustic levitation can be fully reversed. If properly enlightened, some particles can be violently ejected from the aggregation area, while staying inside the levitation plane.

Standard acoustic focusing of particles and aggregation in the leviation plane (a-c). If enlightened with the proper optical wavelength the particles can be ejected radially but remaining in the levitation plane.

Example of ejection of fluorescent particles. In the first part of the movie, the particles gather to form a large aggregate in the levitation plane. In the second part of the video, the particles are ejected when illuminated with their absorption wavelength.