{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,9]],"date-time":"2026-06-09T05:57:24Z","timestamp":1780984644549,"version":"3.54.1"},"reference-count":40,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,8,27]],"date-time":"2022-08-27T00:00:00Z","timestamp":1661558400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key Research and Development Program","award":["2021YFB3601404"],"award-info":[{"award-number":["2021YFB3601404"]}]},{"name":"National Key Research and Development Program","award":["61675238"],"award-info":[{"award-number":["61675238"]}]},{"name":"National Key Research and Development Program","award":["61975247"],"award-info":[{"award-number":["61975247"]}]},{"name":"National Key Research and Development Program","award":["61775244"],"award-info":[{"award-number":["61775244"]}]},{"name":"National Natural Science Foundation of China (NSFC)","award":["2021YFB3601404"],"award-info":[{"award-number":["2021YFB3601404"]}]},{"name":"National Natural Science Foundation of China (NSFC)","award":["61675238"],"award-info":[{"award-number":["61675238"]}]},{"name":"National Natural Science Foundation of China (NSFC)","award":["61975247"],"award-info":[{"award-number":["61975247"]}]},{"name":"National Natural Science Foundation of China (NSFC)","award":["61775244"],"award-info":[{"award-number":["61775244"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A novel all-pass slot microring resonator (SMRR), intended for label-free optical biosensing based on silicon-on-insulator platforms, is proposed. The sensor consists of a bent asymmetric directional coupler and an asymmetric-slot microring waveguide. The appropriate slot width of 140 nm is identified by the three-dimensional finite-difference time-domain (3D-FDTD) method for better light\u2013matter interaction in applications. According to numerical calculations, the SMRR sensor with a footprint of 10 \u00b5m \u00d7 10 \u00b5m has a concentration sensitivity of 725.71 pm\/% for sodium chloride (NaCl) solutions. The corresponding refractive index sensitivity is 403 nm\/RIU (refractive index unit), which is approximately six times greater than that of traditional microring resonator sensors. A low detection limit of 0.129% is also achieved. This SMRR is an excellent candidate for label-free optical biosensors due to its compact structure and excellent sensing capability.<\/jats:p>","DOI":"10.3390\/s22176467","type":"journal-article","created":{"date-parts":[[2022,8,30]],"date-time":"2022-08-30T01:37:55Z","timestamp":1661823475000},"page":"6467","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Compact Slot Microring Resonator for Sensitive and Label-Free Optical Sensing"],"prefix":"10.3390","volume":"22","author":[{"given":"Bingyao","family":"Shi","sequence":"first","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiao","family":"Chen","sequence":"additional","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanyuan","family":"Cai","sequence":"additional","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuai","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yiquan","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Science, Minzu University of China, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"S561","DOI":"10.1088\/1464-4258\/8\/7\/S41","article-title":"Optical biosensor microsystems based on the integration of highly sensitive Mach-Zehnder interferometer devices","volume":"8","author":"Moreno","year":"2006","journal-title":"J. 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