Tighter focusing with a parabolic mirror

TLDR

All have text. So produce 4 sentences in order: Background, Mechanism, Findings, Other. Background: "Tighter focusing with a parabolic mirror" context: The abstract says: "The results stand in accordance with the theoretical calculations presented by Davidson and Bokor, who predicted a reduction in the total focal spot size of 43% as compared with an aplanatic lens." So background: general context: parabolic mirrors can reduce focal spot size compared to aplanatic lens. So sentence: "Parabolic mirrors can reduce focal spot size by about 43% compared to aplanatic lenses, as predicted by theory." That covers background.

Abstract

We demonstrate experimentally and theoretically that a parabolic mirror (PM) with a high numerical aperture (NA) of 1 focuses a radially polarized laser mode to the smallest diffraction-limited spot at a fixed NA and wavelength, having an area of 0.134 lambda(2). The measurements were performed with a confocal microscope, using the PM as a focusing and collecting element. The results stand in accordance with the theoretical calculations presented by Davidson and Bokor [Opt. Lett. 29, 1318 (2004)], who predicted a reduction in the total focal spot size of 43% as compared with an aplanatic lens.