Resolving Discrepancy between Theoretical and Experimental Optical Trapping Forces Using Effects of Beam Waist and Trapping Position Displacement due to Gravity

Ukita, Hiroo; Saitoh, Takashi; Sakahara, Noboru

doi:10.1007/s10043-006-0436-4

Cited by 1 publication

(1 citation statement)

References 14 publications

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“…Since optical tweezers were first introduced by Ashkin in 1970 [1] to trap dielectric beads in lowerrefractive-index media, the optical trap has become an indispensable tool for manipulating micrometerscale objects without any mechanical contact, particularly in the biosciences [2][3][4][5][6]. Unfortunately, traditional far-field optical traps face trapping size limitations based on the diffraction limits; in particular, considering an object of radius r, the trapping efficiency drops rapidly (following ∼ r 3 law).…”

Section: Introductionmentioning

confidence: 99%

Low-Power Far Field Nanonewton Optical Force Trapping Based on Far-Field Nanofocusing Plasmonic Lens

Cao¹,

Cheng²

2016

PIER M

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Abstract-In this article, we study the far-field trapping behavior of dielectric nanospheres with diameter of 200 nm by utilizing a plasmon enhanced far-field nanofocusing lens. Based on our high effect nanofocusing circular plasmonic lens, such a far-field plasmonic trap is constituted by illuminating with a laser to form a sharper focus (subwavelength) due to a constructive interference of cylindrical surface plasmon wave. The nanoparticles can be steadily trapped in the far-field focal region (4.4λ) with an optical force to nanonewton (−4.76 nN) order, and the required optical power is less than 0.5 W. Compared with other surface plasmon tweezers, the proposed far-field plasmonic tweezers can not only avoid physical contact with the trapped particles to prevent contamination and reduce thermal damage effects due to metal absorption, but also enable the easy trapping and manipulation of nanosize dielectric particles owing to nanonewton scale forces.

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