{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T03:33:49Z","timestamp":1774928029163,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,11]],"date-time":"2021-03-11T00:00:00Z","timestamp":1615420800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-032057; POCI-01-0145-FEDER-029282; SFRH\/BD\/144226\/2019"],"award-info":[{"award-number":["POCI-01-0145-FEDER-032057; POCI-01-0145-FEDER-029282; SFRH\/BD\/144226\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 \u00b5m period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth &lt; 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).<\/jats:p>","DOI":"10.3390\/s21061977","type":"journal-article","created":{"date-parts":[[2021,3,11]],"date-time":"2021-03-11T20:17:40Z","timestamp":1615493860000},"page":"1977","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["UV Inscription and Pressure Induced Long-Period Gratings through 3D Printed Amplitude Masks"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7973-6891","authenticated-orcid":false,"given":"Ricardo","family":"Oliveira","sequence":"first","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9716-6984","authenticated-orcid":false,"given":"Liliana M.","family":"Sousa","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6528-9034","authenticated-orcid":false,"given":"Ana M.","family":"Rocha","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4156-8984","authenticated-orcid":false,"given":"Rog\u00e9rio","family":"Nogueira","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8804-593X","authenticated-orcid":false,"given":"L\u00facia","family":"Bilro","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Campus Universit\u00e1rio de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1109\/50.476137","article-title":"Long-period fiber gratings as band-rejection filters","volume":"14","author":"Vengsarkar","year":"1996","journal-title":"J. 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