Optical measurement of interaction potentials between a single microparticle and an evanescent field

Ken Ichiro Wada*, Keiji Sasaki, Hiroshi Masuhara

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Radiation pressure exerted on a single microparticle within an evanescent field has been analyzed by a three-dimensional potential measurement system. Temporal fluctuation of the particle position due to the thermal Brownian motion was sequentially measured, and the potential energy was estimated by a thermodynamical analysis. A potential profile corresponding to the evanescent-field-induced radiation pressure could be obtained as an energy difference between two potentials measured with and without illumination of the evanescent field. The exponential dependence on the longitudinal position was clearly observed. The lateral radiation force on a 4.5 μm polystyrene latex particle in water was determined to be 90 fN at the laser intensity of 1.0 kW cm-2.

Original languageEnglish
Pages (from-to)2815-2817
Number of pages3
JournalApplied Physics Letters
Volume76
Issue number20
DOIs
StatePublished - 15 May 2000

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