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Express"],"published-print":{"date-parts":[[2026,1,26]]},"abstract":"<jats:p>\n                    We present a novel method for generating an extremely confined nanoscale light field using an all-dielectric conical nanotip coupled to a microfiber. By launching a radially polarized TM\n                    <jats:sub>01<\/jats:sub>\n                    mode into the tip, we achieve constructive interference of longitudinal electric field components at the apex, resulting in a highly localized optical hotspot with sub-10\u2005nm dimensions and a mode volume as small as 10\n                    <jats:sup>\u22127<\/jats:sup>\n                    \u03bb\n                    <jats:sup>3<\/jats:sup>\n                    . This approach overcomes the limitations of conventional dielectric tips and rivals plasmonic superfocusing without incurring ohmic losses. Numerical simulations reveal that the focal spot features a high intensity enhancement ratio (&gt; 3500), strong peak-to-background contrast (&gt; 30\u2005dB), and circular symmetry. Furthermore, we demonstrate the ability to shape the light field into arbitrary nanoscale patterns by modifying the tip geometry. These findings open new avenues for low-loss, high-precision light confinement in applications such as optical nano tweezers, nanoscopy, nano lasers, and nanoparticle spectroscopy.\n                  <\/jats:p>","DOI":"10.1364\/oe.580482","type":"journal-article","created":{"date-parts":[[2026,1,2]],"date-time":"2026-01-02T07:00:07Z","timestamp":1767337207000},"page":"2181","update-policy":"https:\/\/doi.org\/10.1364\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Enhanced optical superfocusing effect at an all-dielectric nanocone tip"],"prefix":"10.1364","volume":"34","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-9849-9021","authenticated-orcid":true,"given":"Weinan","family":"Feng","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00ntfnx83","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Makoto","family":"Tsubokawa","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00ntfnx83","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"285","published-online":{"date-parts":[[2026,1,16]]},"reference":[{"key":"oe-34-2-2181-R1","doi-asserted-by":"publisher","first-page":"30","DOI":"10.1038\/s41377-024-01380-x","type":"journal-article","volume":"13","author":"Koo","year":"2024","journal-title":"Light: Sci. 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