{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T14:41:04Z","timestamp":1773931264511,"version":"3.50.1"},"reference-count":32,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2019,9,1]],"date-time":"2019-09-01T00:00:00Z","timestamp":1567296000000},"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>In this paper, a low-loss, spiral lattice photonic crystal fiber (PCF)-based plasmonic biosensor is proposed for its application in detecting various biomolecules (i.e., sugar, protein, DNA, and mRNA) and biochemicals (i.e., serum and urine). Plasmonic material gold (Au) is employed externally to efficiently generate surface plasmon resonance (SPR) in the outer surface of the PCF. A thin layer of titanium oxide (TiO2) is also introduced, which assists in adhering the Au layer to the silica fiber. The sensing performance is investigated using a mode solver based on the finite element method (FEM). Simulation results show a maximum wavelength sensitivity of 23,000 nm\/RIU for a bio-samples refractive index (RI) detection range of 1.32\u20131.40. This sensor also exhibits a very low confinement loss of 0.22 and 2.87 dB\/cm for the analyte at 1.32 and 1.40 RI, respectively. Because of the ultra-low propagation loss, the proposed sensor can be fabricated within several centimeters, which reduces the complexity related to splicing, and so on.<\/jats:p>","DOI":"10.3390\/s19173794","type":"journal-article","created":{"date-parts":[[2019,9,2]],"date-time":"2019-09-02T03:16:12Z","timestamp":1567394172000},"page":"3794","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":65,"title":["A Bimetallic-Coated, Low Propagation Loss, Photonic Crystal Fiber Based Plasmonic Refractive Index Sensor"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2900-5350","authenticated-orcid":false,"given":"Mohammad Al","family":"Mahfuz","sequence":"first","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Independent University Bangladesh (IUB), Dhaka 1229, Bangladesh"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8215-780X","authenticated-orcid":false,"given":"Md. Anwar","family":"Hossain","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Green University of Bangladesh, Dhaka 1207, Bangladesh"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emranul","family":"Haque","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Independent University Bangladesh (IUB), Dhaka 1229, Bangladesh"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nguyen Hoang","family":"Hai","sequence":"additional","affiliation":[{"name":"School of Electronics and Telecommunication, Hanoi University of Science and Technology, Hanoi 100000, Vietnam"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshinori","family":"Namihira","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, University of the Ryukyus, Nishihara 151-0066, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Feroz","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronic Engineering, Independent University Bangladesh (IUB), Dhaka 1229, Bangladesh"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,9,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.yofte.2018.03.008","article-title":"A Review of advancements (2007\u20132017) in plasmonics- based optical fiber sensors","volume":"43","author":"Sharma","year":"2018","journal-title":"Opt. Fiber Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2068","DOI":"10.1364\/AO.58.002068","article-title":"Design and fabrication of copper-filled photonic crystal fiber based polarization filters","volume":"58","author":"Azman","year":"2019","journal-title":"Appl. Opt."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.yofte.2019.03.013","article-title":"Theoretical analysis of all-solid D-type photonic crystal fiber based plasmonic sensor for refractive index and temperature sensing","volume":"50","author":"Zao","year":"2019","journal-title":"Opt. Fiber Technol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1016\/j.optmat.2017.12.049","article-title":"Hollow-core silver coated photonic crystal fiber plasmonic sensor","volume":"76","author":"Momota","year":"2018","journal-title":"Opt. Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/j.optmat.2019.02.012","article-title":"Highly sensitive photonic crystal fiber plasmonic biosensor: Design and analysis","volume":"90","author":"Mahfuz","year":"2019","journal-title":"Opt. Mater."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"9039","DOI":"10.1364\/OE.26.009039","article-title":"Symmetrical dual d-shape photonic crystal fibers for surface plasmon resonance sensing","volume":"26","author":"Liu","year":"2018","journal-title":"Opt. Express"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2776","DOI":"10.1109\/JSEN.2017.2677473","article-title":"Highly sensitive D-shaped photonic crystal fiber based plasmonic biosensor in visible to near-IR","volume":"17","author":"Rifat","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1016\/j.snb.2016.11.113","article-title":"Photonic crystal fiber based plasmonic sensors","volume":"243","author":"Rifat","year":"2017","journal-title":"Sens. Actuator. B. Chem."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Hasan, M.R., Akter, S., Rifat, A.A., Rana, S., and Ali, S. (2017). A Highly Sensitive Gold-Coated Photonic Crystal Fiber Biosensor Based on Surface Plasmon Resonance. Photonics, 4.","DOI":"10.3390\/photonics4010018"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.optlastec.2018.03.019","article-title":"Ultra-wide bandwidth polarization filter based on gold-coated photonic crystal fiber around the wavelength of 1.55 \u00b5m","volume":"106","author":"Wang","year":"2018","journal-title":"Opt. Laser Tech."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5761","DOI":"10.1109\/JSEN.2018.2841035","article-title":"Twin core photonic crystal fiber plasmonic refractive index sensor","volume":"18","author":"Paul","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5268","DOI":"10.1364\/AO.57.005268","article-title":"D-shaped photonic crystal fiber plasmonic refractive index sensor based on gold grating","volume":"57","author":"Lu","year":"2018","journal-title":"Appl. Opt."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"30347","DOI":"10.1364\/OE.26.030347","article-title":"Dual-polarized highly sensitive plasmonic sensor in the visible to near-IR spectrum","volume":"26","author":"Islam","year":"2018","journal-title":"Opt. Express"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1123","DOI":"10.1007\/s11468-015-9912-7","article-title":"On the Performance of Graphene-Based D-Shaped Photonic Crystal Fibre Biosensor Using Surface Plasmon Resonance","volume":"10","author":"Dash","year":"2015","journal-title":"Plasmonics"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1007\/s11082-018-1397-0","article-title":"Highly sensitive photonic crystal fiber biosensor based on titanium nitride","volume":"50","author":"Khalil","year":"2018","journal-title":"Opt. Quant. Electron."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1007\/s11468-016-0301-7","article-title":"Highly sensitive SPR sensor based on d-shaped photonic crystal fiber coated with indium tin oxide at near-infrared wavelength","volume":"12","author":"Huang","year":"2016","journal-title":"Plasmonics"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1109\/LPT.2017.2786475","article-title":"Plasmonic refractive index sensor employing niobium nanofilm on photonic crystal fiber","volume":"30","author":"Hasan","year":"2018","journal-title":"IEEE Photon. Tech. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"79085","DOI":"10.1109\/ACCESS.2019.2922663","article-title":"A Hi-Bi Ultra-Sensitive Surface Plasmon Resonance Fiber Sensor","volume":"7","author":"Islam","year":"2019","journal-title":"IEEE Access"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1364\/OL.43.000891","article-title":"Highly sensitive selectively coated photonic crystal fiber-based plasmonic sensor","volume":"43","author":"Rifat","year":"2018","journal-title":"Opt. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"465","DOI":"10.1007\/s11468-016-0286-2","article-title":"Extra-broad photonic crystal fiber refractive index sensor based on surface plasmon resonance","volume":"12","author":"An","year":"2017","journal-title":"Plasmonics"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1505","DOI":"10.1007\/s11468-016-0203-8","article-title":"Highly sensitive side-polished birefringent PCF based SPR sensor in near IR","volume":"11","author":"Dash","year":"2016","journal-title":"Plasmonics"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"85768582","DOI":"10.1364\/OE.23.008576","article-title":"Surface plasmon resonance sensor based on D-shaped microstructured optical fiber with hollow core","volume":"23","author":"Luan","year":"2015","journal-title":"Opt. Express"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"8287","DOI":"10.1109\/JSEN.2018.2865514","article-title":"Surface plasmon resonance sensor based on modified D-shaped photonic crystal fiber for wider range of refractive index detection","volume":"18","author":"Haque","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"102328","DOI":"10.1016\/j.rinp.2019.102328","article-title":"Highly Sensitive Open-Channels Based Plasmonic Biosensor in Visible to Near-Infrared Wavelength","volume":"13","author":"Akter","year":"2019","journal-title":"Results Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1550","DOI":"10.1364\/JOSAB.26.001550","article-title":"Photonic crystal fiber-based plasmonic sensors for the detection of bio layer thickness","volume":"26","author":"Hassani","year":"2009","journal-title":"J. Opt. Soc. Am. B"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.yofte.2018.04.009","article-title":"Groove micro-structure optical fiber refractive index sensor with nanoscale gold film based on surface plasmon resonance","volume":"43","author":"Zhang","year":"2018","journal-title":"Opt. Fiber Tech."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1883","DOI":"10.1364\/AO.57.001883","article-title":"High-sensitivity birefringent and single-layer coating photonic crystal fiber biosensor based on surface plasmon resonance","volume":"57","author":"Liu","year":"2018","journal-title":"Appl. Opt."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.yofte.2019.03.028","article-title":"Surface plasmon resonance photonic crystal fiber biosensor based on gold graphene layers","volume":"50","author":"Lou","year":"2019","journal-title":"Opt. Fiber Tech."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1109\/JSEN.2017.2769720","article-title":"Spiral photonic crystal fiber based dual-polarized surface plasmon resonance biosensor","volume":"18","author":"Hasan","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1713","DOI":"10.1364\/OSAC.2.001713","article-title":"Asymmetrical photonic crystal fiber based plasmonic sensor using the lower birefringence peak method","volume":"2","author":"Mahfuz","year":"2019","journal-title":"OSA Continuum"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1109\/LPT.2012.2236309","article-title":"Stacking the equiangular spiral","volume":"25","author":"Agrawal","year":"2013","journal-title":"IEEE Photon. Technol. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1547","DOI":"10.1364\/AO.58.001547","article-title":"Microchannel-based plasmonic refractive index sensor for low refractive index detection","volume":"58","author":"Haque","year":"2019","journal-title":"Appl. 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