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Focusing a radially polarized light beam to a significantly smaller spot size

R. Dorn·S. Quabis·G. Leuchs
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Abstract

We experimentally demonstrate for the first time that a radially polarized field can be focussed to a spot size significantly smaller (0.16(1) lambda^2) than for linear polarization (0.26 lambda^2). The effect of the vector properties of light is shown by a comparison of the focal intensity distribution for radially and azimuthally polarized input fields. For strong focusing a radially polarized field leads to a longitudinal electric field component at the focus which is sharp and centered at the optical axis. The relative contribution of this component is enhanced by using an annular aperture.

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R. Dorn, S. Quabis, G. Leuchs. 2003-10-01. Focusing a radially polarized light beam to a significantly smaller spot size. https://arxiv.org/abs/physics/0310007

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