{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T07:18:10Z","timestamp":1768720690525,"version":"3.49.0"},"reference-count":61,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,3,1]],"date-time":"2021-03-01T00:00:00Z","timestamp":1614556800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>High-sensitivity and simple, low-cost readout are desirable features for sensors independent of the application area. Micro-cantilever sensors use the deflection induced by the analyte presence to achieve high-sensitivity but possess complex electronic readouts. Current holographic sensors probe the analyte presence by measuring changes in their optical properties, have a simpler low-cost readout, but their sensitivity can be further improved. Here, the two working principles were combined to obtain a new hybrid sensor with enhanced sensitivity. The diffractive element, a holographically patterned thin photopolymer layer, was placed on a polymer (polydimethylsiloxane) layer forming a bi-layer macro-cantilever. The different responses of the layers to analyte presence lead to cantilever deflection. The sensitivity and detection limits were evaluated by measuring the variation in cantilever deflection and diffraction efficiency with relative humidity. It was observed that the sensitivity is tunable by controlling the spatial frequency of the photopolymer gratings and the cantilever thickness. The sensor deflection was also visible to the naked eye, making it a simple, user-friendly device. The hybrid sensor diffraction efficiency response to the target analyte had an increased sensitivity (10-fold when compared with the cantilever or holographic modes operating independently), requiring a minimum upturn in the readout complexity.<\/jats:p>","DOI":"10.3390\/s21051673","type":"journal-article","created":{"date-parts":[[2021,3,1]],"date-time":"2021-03-01T03:35:40Z","timestamp":1614569740000},"page":"1673","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity"],"prefix":"10.3390","volume":"21","author":[{"given":"Catherine","family":"Grogan","sequence":"first","affiliation":[{"name":"School of Physics and Clinical and Optometric Sciences, Technological University Dublin Grangegorman, D07EWV4 Dublin, Ireland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0224-1855","authenticated-orcid":false,"given":"Faolan Radford","family":"McGovern","sequence":"additional","affiliation":[{"name":"School of Physics and Clinical and Optometric Sciences, Technological University Dublin Grangegorman, D07EWV4 Dublin, Ireland"},{"name":"Centre for Industrial and Engineering Optics, Technological University Dublin, FOCAS Research Institute, Camden Row, D08 CKP1 Dublin, Ireland"}]},{"given":"Rory","family":"Staines","sequence":"additional","affiliation":[{"name":"School of Physics and Clinical and Optometric Sciences, Technological University Dublin Grangegorman, D07EWV4 Dublin, Ireland"},{"name":"Centre for Industrial and Engineering Optics, Technological University Dublin, FOCAS Research Institute, Camden Row, D08 CKP1 Dublin, Ireland"}]},{"given":"George","family":"Amarandei","sequence":"additional","affiliation":[{"name":"School of Physics and Clinical and Optometric Sciences, Technological University Dublin Grangegorman, D07EWV4 Dublin, Ireland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0810-2197","authenticated-orcid":false,"given":"Izabela","family":"Naydenova","sequence":"additional","affiliation":[{"name":"School of Physics and Clinical and Optometric Sciences, Technological University Dublin Grangegorman, D07EWV4 Dublin, Ireland"},{"name":"Centre for Industrial and Engineering Optics, Technological University Dublin, FOCAS Research Institute, Camden Row, D08 CKP1 Dublin, Ireland"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2894","DOI":"10.1063\/1.111407","article-title":"Thermal and ambient-induced deflections of scanning force microscope cantilevers","volume":"64","author":"Thundat","year":"1994","journal-title":"Appl. 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