{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T22:09:12Z","timestamp":1791324552319,"version":"4.3.1"},"reference-count":23,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2013,10,28]],"date-time":"2013-10-28T00:00:00Z","timestamp":1382918400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We investigate a highly sensitive optical sensor based on two cascaded microring resonators exploiting the Vernier effect. The architecture consists of two microrings with a slight difference in their free spectral ranges. This allows the generation of the Vernier effect for achieving ultra-high sensitivities. The sensor chip was fabricated using a silicon nitride platform and characterized with isopropanol\/ethanol mixtures. A sensitivity of 0.95 nm\/% was found for isopropanol concentrations in ethanol ranging from 0% to 10%. Furthermore, a collection of measurements was carried out using aqueous sodium chloride (NaCl) in solutions of different concentrations, confirming a high sensitivity of 10.3 nm\/% and a bulk refractive index sensitivity of 6,317 nm\/RIU. A limit of detection of 3.16 \u00b4 10\u22126 RIU was determined. These preliminary results show the potential features of cascaded silicon nitride microring resonators for real-time and free-label monitoring of biomolecules for a broad range of applications.<\/jats:p>","DOI":"10.3390\/s131114601","type":"journal-article","created":{"date-parts":[[2013,10,28]],"date-time":"2013-10-28T12:00:27Z","timestamp":1382961627000},"page":"14601-14610","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["A Highly Sensitive Refractometric Sensor Based on Cascaded SiN Microring Resonators"],"prefix":"10.3390","volume":"13","author":[{"given":"Vanessa","family":"Zamora","sequence":"first","affiliation":[{"name":"Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, Berlin 10587, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"L\u00fctzow","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, Berlin 10587, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Weiland","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, Berlin 10587, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Pergande","sequence":"additional","affiliation":[{"name":"Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, Berlin 10587, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2013,10,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2096","DOI":"10.1109\/LPT.2006.883210","article-title":"A polymer microdisk photonic sensor integrated onto silicon","volume":"18","author":"Cho","year":"2006","journal-title":"IEEE Photon. 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