We investigate dynamics and interactions of particles levitated and trapped by the thermophoretic force in a vacuum cell. Our analysis is based on footage taken by orthogonal cameras that are able to capture the three dimensional trajectories of the particles. In contrast to spherical particles, which remain stationary at the center of the cell, here we report new qualitative features of the motion of particles with non-spherical geometry. Singly levitated particles exhibit steady spinning around their body axis and rotation around the symmetry axis of the cell. When two levitated particles approach each other, repulsive or attractive interactions between the particles are observed. Our levitation system offers a wonderful platform to study interaction between particles in a microgravity environment.

Date Published: 25 August 2017
PDF: 6 pages
Proc. SPIE 10347, Optical Trapping and Optical Micromanipulation XIV, 103471Z (25 August 2017); doi: 10.1117/12.2277140

Published in SPIE Proceedings Vol. 10347:
Optical Trapping and Optical Micromanipulation XIV
Kishan Dholakia; Gabriel C. Spalding, Editor(s)