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Optical trapping of selected dielectric microparticles in air


Haesung Park, Thomas W. LeBrun


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.
The Journal of Visualized Experiments


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


Park, H. and LeBrun, T. (1970), Optical trapping of selected dielectric microparticles in air, The Journal of Visualized Experiments (Accessed April 18, 2024)
Created May 7, 2017, Updated February 19, 2017