title: Periodic oscillation of a colloidal disk near a wall in an optical trap.
abstract: Colloidal disks can be stably trapped using optical tweezers. However, when the tweezers press the disk against an opposing wall, we observe an instability leading to periodic motion which we model using coupled nonlinear equations. The resulting "switchback" oscillation involves combined orientational and translational motion of the disk. This observation reveals a new degree of freedom in colloidal architectures, that is, the ability to drive translational motion from a static light field energy source.
authors.affiliation: Corporate Strategic Research, ExxonMobil Research and Engineering Company, Route 22 East, Annandale, New Jersey 08801, USA. zcheng@deas.harvard.edu
authors.forename: Zhengdong
authors.initials: Z
authors.lastname: Cheng
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Mason
authors.forename: P M
authors.initials: PM
authors.lastname: Chaikin