Transient trapping of two microparticles interacting with optical tweezers and cavitation bubbles

Characterization of microparticles with driven optical tweezers.

We discuss how actively-driven optical tweezers may be used to characterize Brownian microparticles. Two experiments are described in detail. We follow the thermal fluctuations of a charged particle in an oscillatory electric field and demonstrate that charges as low as a few elementary charges can be measured accurately and reproducibly. Secondly, we measure the orientational dynamics of a tra...

Independent trapping and manipulation of microparticles using dexterous acoustic tweezers

Measuring Trapping Forces in Optical Tweezers

Introduction Since the work of Ashkin on radiation pressure, the possibility to use the optical force of optical fields to trap and manipulate microparticles has found a wide range of applications. From atomic and nonlinear physics to biology, optical forces have provided a convenient way to control the dynamics of small particles.Optical tweezers, for example, have proved useful not only for t...

Simulation and optimization of the trapping efficiency in optical tweezers

Light-induced rotations of chiral birefringent microparticles in optical tweezers

We study the rotational dynamics of solid chiral and birefringent microparticles induced by elliptically polarized laser light in optical tweezers. We find that both reflection of left circularly polarized light and residual linear retardance affect the particle dynamics. The degree of ellipticity of laser light needed to induce rotations is found. The experimental results are compared with ana...