Optical trapping of selected dielectric microparticles in air

Author(s)

Haesung Park, Thomas W. LeBrun

Abstract

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (which we refer to as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner.

Citation

The Journal of Visualized Experiments

Pub Type

Journals

Keywords

optical levitation, optical trapping, dielectric microparticles, piezoelectric transducer, electrostatic modulation

Citation

Park, H. and LeBrun, T. (1970), Optical trapping of selected dielectric microparticles in air, The Journal of Visualized Experiments (Accessed October 28, 2025)