Non-conservative forces in optical tweezers and Brownian vortexes

Bo Sun; Alexander Y. Grosberg; David G. Grier

doi:10.1117/12.839922

8 February 2010 Non-conservative forces in optical tweezers and Brownian vortexes

Bo Sun, Alexander Y. Grosberg, David G. Grier

Proceedings Volume 7613, Complex Light and Optical Forces IV; 76130A (2010) https://doi.org/10.1117/12.839922
Event: SPIE OPTO, 2010, San Francisco, California, United States

Abstract

Mechanical equilibrium at zero temperature does not necessarily imply thermodynamic equilibrium at finite temperature for a particle confined by a static, but non-conservative force field. Instead, the diffusing particle can enter into a steady state characterized by toroidal circulation in the probability flux, which we call a Brownian vortex. The circulatory bias in the particle's thermally-driven trajectory is not simply a deterministic response to the solenoidal component of the force, but rather reflects an interplay between advection and diffusion in which thermal fluctuations extract work from the non-conservative force field. As an example of this previously unrecognized class of stochastic machines, we consider a colloidal sphere diffusing in a conventional optical tweezer. We demonstrate both theoretically and experimentally that non-conservative optical forces bias the particle's fluctuations into toroidal vortexes whose circulation can reverse direction with temperature or laser power.

Citation Download Citation

Bo Sun, Alexander Y. Grosberg, and David G. Grier "Non-conservative forces in optical tweezers and Brownian vortexes", Proc. SPIE 7613, Complex Light and Optical Forces IV, 76130A (8 February 2010); https://doi.org/10.1117/12.839922

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available