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arXiv · 1006.3619

Subwavelength focusing of light by a tapered microtube

Jian Fu·Hongtao Dong·Wei Fang
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Abstract

We propose a mechanism for subwavelength focusing at optical frequencies based on the use of a tapered microtube fabricated from a glass capillary tube. Using coherent illumination at 671nm and a near-field scanning optical microscope probe which was mounted on a 3-axis piezo nanopositioning stage, a sequence of 2-D intensity profiles were obtained. Our experimental results reveal the smallest focal spot with a near diffraction-limited full width at half-maximum of ~435nm(0.65λ)at a distance of ~1.47μm (2.2λ) from the output endface of microtube. The experimental results are in excellent agreement with our numerical simulation.

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Jian Fu, Hongtao Dong, Wei Fang. 2010-06-18. Subwavelength focusing of light by a tapered microtube. https://doi.org/10.1063/1.3472224

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