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Updated: Aug 2, 2026

A Microfluidic-based Hydrodynamic Trap for Single Particles
Published on: January 21, 2011
Trapping Microparticles in a Structured Dark Focus
F Almeida1, I Sousa1, O Kremer2
1Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Abstract:
We experimentally demonstrate stable trapping and controlled manipulation of silica microspheres in a structured optical beam consisting of a dark focus surrounded by light in all directions-the dark focus tweezer. Results from power spectrum and potential analysis demonstrate the nonharmonicity of the trapping potential landscape, which is reconstructed from experimental data in agreement to Lorentz-Mie numerical simulations. Applications of the dark tweezer in levitated optomechanics and biophysics are discussed.
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