{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T04:30:39Z","timestamp":1772253039316,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2019,11,19]],"date-time":"2019-11-19T00:00:00Z","timestamp":1574121600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61575076, 61875069, 61605057 and 61675087"],"award-info":[{"award-number":["61575076, 61875069, 61605057 and 61675087"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Science and Technology Development Plan of Jilin Provincial","award":["20190302010GX"],"award-info":[{"award-number":["20190302010GX"]}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"publisher","award":["2019jcxk-59"],"award-info":[{"award-number":["2019jcxk-59"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, we present and analyze a compact inner-wall grating slot microring resonator (IG-SMRR) with the footprint of less than 13 \u03bcm \u00d7 13 \u03bcm on the silicon-on-insulator (SOI) platform for label-free sensing, which comprises a slot microring resonator (SMRR) and inner-wall grating (IG). Its detection range is significantly enhanced without the limitation of the free spectral region (FSR) owing to the combination of SMRR and IG. The IG-SMRR has an ultra-large quasi-FSR of 84.5 nm as the detection range, and enlarged factor is up to over 3 compared with the conventional SMRR. The concentration sensitivities of sodium chloride solutions and D-glucose solutions are 996.91 pm\/% and 968.05 pm\/%, respectively, and the corresponding refractive index (RI) sensitivities are 559.5 nm\/RIU (refractive index unit) and 558.3 nm\/RIU, respectively. The investigation on the combination of SMRR and IG is a valuable exploration of label-free sensing application for ultra-large detection range and ultra-high sensitivity in future.<\/jats:p>","DOI":"10.3390\/s19225038","type":"journal-article","created":{"date-parts":[[2019,11,19]],"date-time":"2019-11-19T11:30:17Z","timestamp":1574163017000},"page":"5038","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Compact Inner-Wall Grating Slot Microring Resonator for Label-Free Sensing"],"prefix":"10.3390","volume":"19","author":[{"given":"Hongjun","family":"Gu","sequence":"first","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"},{"name":"College of Information Technology, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"He","family":"Gong","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"},{"name":"College of Information Technology, Jilin Agricultural University, 2888 Xincheng Street, Changchun 130118, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chunxue","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaoqiang","family":"Sun","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xibin","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8471-4689","authenticated-orcid":false,"given":"Yunji","family":"Yi","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Changming","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fei","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daming","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.aca.2008.05.022","article-title":"Sensitive optical biosensors for unlabeled targets: A review","volume":"620","author":"Fan","year":"2008","journal-title":"Anal. 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