{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T06:26:47Z","timestamp":1785824807346,"version":"3.56.0"},"reference-count":28,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2016,3,9]],"date-time":"2016-03-09T00:00:00Z","timestamp":1457481600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000923","name":"Australian Research Council","doi-asserted-by":"publisher","award":["DP 120 103703"],"award-info":[{"award-number":["DP 120 103703"]}],"id":[{"id":"10.13039\/501100000923","id-type":"DOI","asserted-by":"publisher"}]},{"name":"ERC \u2018TOSCA\u2019 programme","award":["247375"],"award-info":[{"award-number":["247375"]}]},{"DOI":"10.13039\/501100000288","name":"The Royal Society","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000288","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001320","name":"Wolfson Foundation","doi-asserted-by":"publisher","award":["WM110032"],"award-info":[{"award-number":["WM110032"]}],"id":[{"id":"10.13039\/501100001320","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001320","name":"Wolfson Foundation","doi-asserted-by":"publisher","award":["WM150029"],"award-info":[{"award-number":["WM150029"]}],"id":[{"id":"10.13039\/501100001320","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000921","name":"European Cooperation in Science and Technology","doi-asserted-by":"publisher","award":["BM1205"],"award-info":[{"award-number":["BM1205"]}],"id":[{"id":"10.13039\/501100000921","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Queensland Government\u2019s Smart Futures Fellowships programme"},{"name":"EPSRC (UK)","award":["EP\/J002356\/1"],"award-info":[{"award-number":["EP\/J002356\/1"]}]},{"name":"EPSRC (UK)","award":["EP\/I026657\/1"],"award-info":[{"award-number":["EP\/I026657\/1"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We propose a self-consistent method for the analysis of granular materials at terahertz (THz) frequencies using a quantum cascade laser. The method is designed for signals acquired from a laser feedback interferometer, and applied to non-contact reflection-mode sensing. Our technique is demonstrated using three plastic explosives, achieving good agreement with reference measurements obtained by THz time-domain spectroscopy in transmission geometry. The technique described in this study is readily scalable: replacing a single laser with a small laser array, with individual lasers operating at different frequencies will enable unambiguous identification of select materials. This paves the way towards non-contact, reflection-mode analysis and identification of granular materials at THz frequencies using quantum cascade lasers.<\/jats:p>","DOI":"10.3390\/s16030352","type":"journal-article","created":{"date-parts":[[2016,3,9]],"date-time":"2016-03-09T10:38:02Z","timestamp":1457519882000},"page":"352","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Laser Feedback Interferometry as a Tool for Analysis of Granular Materials at Terahertz Frequencies: Towards Imaging and Identification of Plastic Explosives"],"prefix":"10.3390","volume":"16","author":[{"given":"She","family":"Han","sequence":"first","affiliation":[{"name":"School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1087-2315","authenticated-orcid":false,"given":"Karl","family":"Bertling","sequence":"additional","affiliation":[{"name":"School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Dean","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James","family":"Keeley","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Burnett","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"},{"name":"School of Chemistry, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yah","family":"Lim","sequence":"additional","affiliation":[{"name":"School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Suraj","family":"Khanna","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander","family":"Valavanis","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edmund","family":"Linfield","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1987-4846","authenticated-orcid":false,"given":"A.","family":"Davies","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dragan","family":"Indjin","sequence":"additional","affiliation":[{"name":"School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Taimre","sequence":"additional","affiliation":[{"name":"School of Mathematics and Physics, The University of Queensland, Brisbane QLD 4072, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aleksandar","family":"Raki\u0107","sequence":"additional","affiliation":[{"name":"School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,3,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"241116","DOI":"10.1063\/1.1946192","article-title":"Detection and identification of explosives using terahertz pulsed spectroscopic imaging","volume":"86","author":"Shen","year":"2005","journal-title":"Appl. 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