{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T12:12:18Z","timestamp":1785413538292,"version":"3.56.0"},"reference-count":25,"publisher":"Optica Publishing Group","issue":"11","license":[{"start":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T00:00:00Z","timestamp":1779148800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/doi.org\/10.1364\/OA_License_v2#VOR"},{"start":{"date-parts":[[2026,5,19]],"date-time":"2026-05-19T00:00:00Z","timestamp":1779148800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/opg.optica.org\/policies\/opg-tdm-policy.json"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of\n\t\t\t\t\t\tChina","doi-asserted-by":"crossref","award":["62305309"],"award-info":[{"award-number":["62305309"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"},{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Key Project of Westlake Institute for\n\t\t\t\t\t\tOptoelectronics","award":["2023GD001"],"award-info":[{"award-number":["2023GD001"]}]}],"content-domain":{"domain":["opg.optica.org"],"crossmark-restriction":false},"short-container-title":["Opt. Lett."],"published-print":{"date-parts":[[2026,6,1]]},"abstract":"<jats:p>Femtosecond laser direct writing is highly effective for fabricating\n\t\t\t\t\tthree-dimensional photonic waveguides deep inside ultra-hard crystals.\n\t\t\t\t\tExtending this capability to the surface realm, where waveguides\n\t\t\t\t\tinteract directly with the sample interface, has been challenging due\n\t\t\t\t\tto pronounced susceptibility to structural cracking. To address this,\n\t\t\t\t\twe introduce a strategy that avoids direct laser modification of\n\t\t\t\t\tfragile crystal\u2013air interfaces. Our approach employs a novel,\n\t\t\t\t\tto the best of our knowledge, surface-integrated, partial-ring\n\t\t\t\t\tcladding architecture, unlike the conventional full-ring design for\n\t\t\t\t\tburied waveguides. By precisely controlling the laser focal depth and\n\t\t\t\t\tcladding geometry, we demonstrate crack-free surface waveguides in\n\t\t\t\t\tsapphire with strong optical confinement and a propagation loss of\n\t\t\t\t\t~2\u2009dB\/cm at 1500\u20131600\u2009nm. Experiments and\n\t\t\t\t\tsimulations confirm that buried waveguides with full-ring cladding\n\t\t\t\t\tsupport near-Gaussian modes, whereas partial-ring surface waveguides\n\t\t\t\t\texhibit minor modal distortion owing to interfacial effects. This work\n\t\t\t\t\tadvances the integration of high-performance surface waveguides in\n\t\t\t\t\thard optical materials for applications in surface sensing and\n\t\t\t\t\tphotonic circuits.<\/jats:p>","DOI":"10.1364\/ol.601365","type":"journal-article","created":{"date-parts":[[2026,4,27]],"date-time":"2026-04-27T19:00:09Z","timestamp":1777316409000},"page":"3088","update-policy":"https:\/\/doi.org\/10.1364\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Crack-free, partial-ring cladding surface waveguides in sapphire fabricated by femtosecond laser direct inscription"],"prefix":"10.1364","volume":"51","author":[{"given":"Wei","family":"Lyu","sequence":"first","affiliation":[{"name":"Hangzhou Dianzi University"},{"name":"Westlake Institute for Optoelectronics"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuying","family":"Wang","sequence":"additional","affiliation":[{"name":"Zhejiang University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu","family":"Xie","sequence":"additional","affiliation":[{"name":"Westlake Institute for Optoelectronics"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoyu","family":"Sun","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05hfa4n20","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9084-1521","authenticated-orcid":true,"given":"Ding","family":"Zhao","sequence":"additional","affiliation":[{"name":"Westlake Institute for Optoelectronics"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiaonan","family":"Dong","sequence":"additional","affiliation":[{"name":"University of Chinese Academy of Sciences"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weiwei","family":"Tang","sequence":"additional","affiliation":[{"name":"University of Chinese Academy of Sciences"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianrong","family":"Qiu","sequence":"additional","affiliation":[{"name":"Zhejiang University"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Yan","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05hfa4n20","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Min","family":"Qiu","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05hfa4n20","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Westlake Institute for Optoelectronics"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"285","published-online":{"date-parts":[[2026,5,19]]},"reference":[{"key":"ol-51-11-3088-R1","doi-asserted-by":"publisher","first-page":"e149","DOI":"10.1038\/lsa.2014.30","type":"journal-article","volume":"3","author":"Sugioka","year":"2014","journal-title":"Light Sci. 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All rights,\n\t\t\t\t\tincluding for text and data mining (TDM), Artificial Intelligence (AI)\n\t\t\t\t\ttraining, and similar technologies, are\n\t\t\t\t\treserved.","name":"copyright","label":"Copyright"}]}}