{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T05:50:34Z","timestamp":1768715434060,"version":"3.49.0"},"reference-count":15,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2009,1,16]],"date-time":"2009-01-16T00:00:00Z","timestamp":1232064000000},"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>This work addresses a new configuration that improves the sensitivity of a humidity sensor based on a long-period fiber grating coated with a SiO2-nanospheres film. An intermediate higher refractive index overlay, deposited through Electrostatic Self-Assembly, is placed between the fiber cladding and the humidity sensitive film in order to increase the total effective refractive index of the coating. With this intermediate design, a three-fold improvement in the sensitivity was obtained. Wavelength shifts up to 15 nm against 5 nm were achieved in a humidity range from 20% to 80%.<\/jats:p>","DOI":"10.3390\/s90100519","type":"journal-article","created":{"date-parts":[[2009,1,16]],"date-time":"2009-01-16T10:49:08Z","timestamp":1232102948000},"page":"519-527","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":33,"title":["Sensitivity Improvement of a Humidity Sensor Based on Silica Nanospheres on a Long-Period Fiber Grating"],"prefix":"10.3390","volume":"9","author":[{"given":"Diana","family":"Viegas","sequence":"first","affiliation":[{"name":"-Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal"},{"name":"INESC Porto, Rua Dr. Roberto Frias, 378, 4200-465 Porto, Portugal"}]},{"given":"Javier","family":"Goicoechea","sequence":"additional","affiliation":[{"name":"Universidad P\u00fablica de Navarra, Campus Arrosadia, 31006 Pamplona, Spain"}]},{"given":"Jos\u00e9 Lu\u00eds","family":"Santos","sequence":"additional","affiliation":[{"name":"-Faculdade de Ci\u00eancias da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal"},{"name":"INESC Porto, Rua Dr. Roberto Frias, 378, 4200-465 Porto, Portugal"}]},{"given":"Francisco Moita","family":"Ara\u00fajo","sequence":"additional","affiliation":[{"name":"INESC Porto, Rua Dr. Roberto Frias, 378, 4200-465 Porto, Portugal"}]},{"given":"Lu\u00eds Alberto","family":"Ferreira","sequence":"additional","affiliation":[{"name":"INESC Porto, Rua Dr. Roberto Frias, 378, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3311-0834","authenticated-orcid":false,"given":"Francisco J.","family":"Arregui","sequence":"additional","affiliation":[{"name":"Universidad P\u00fablica de Navarra, Campus Arrosadia, 31006 Pamplona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2229-6178","authenticated-orcid":false,"given":"Ignacio  R.","family":"Matias","sequence":"additional","affiliation":[{"name":"Universidad P\u00fablica de Navarra, Campus Arrosadia, 31006 Pamplona, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2009,1,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1109\/JSEN.2008.917487","article-title":"Optical fiber humidity sensors using nanostructured coatings of SiO2 nanoparticles","volume":"8","author":"Corres","year":"2008","journal-title":"IEEE Sensors J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/j.snb.2004.05.012","article-title":"An evanescent-wave optical fiber relative humidity sensor with enhanced sensitivity","volume":"104","author":"Khidwania","year":"2005","journal-title":"Sens. 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