Optical-trapping of particles in air using parabolic reflectors and a hollow laser beam

Yong Le Pan, Aimable Kalume, Isaac C.D. Lenton, Timo A. Nieminen, Alex B. Stilgoe, Halina Rubinsztein-Dunlop, Leonid A. Beresnev, Chuji Wang, Joshua L. Santarpia

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We present an advanced optical-trapping method that is capable of trapping arbitrary shapes of transparent and absorbing particles in air. Two parabolic reflectors were used to reflect the inner and outer parts of a single hollow laser beam, respectively, to form two counter-propagating conical beams and bring them into a focal point for trapping. This novel design demonstrated high trapping efficiency and strong trapping robustness with a simple optical configuration. Instead of using expensive microscope objectives, the parabolic reflectors can not only achieved large numerical aperture (N.A.) focusing, but were also able to focus the beam far away from optical surfaces to minimize optics contamination. This design also offered a large free space for flexible integration with other measuring techniques, such as optical-trapping Raman spectroscopy, for on-line single particle characterization.

Original languageEnglish (US)
Pages (from-to)33061-33069
Number of pages9
JournalOptics Express
Issue number23
StatePublished - 2019

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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