Pedestal subwavelength grating metamaterial waveguide ring resonator for ultra-sensitive label-free biosensing.

Autor: Chang CW; Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78758, USA; Department of Physics and Center of Crystal Research, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan, ROC., Xu X; Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78758, USA; Omega Optics Inc, 8500 Shoal Creek Blvd, Austin, TX, 78759, USA. Electronic address: xiaochuan.xu@omegaoptics.com., Chakravarty S; Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78758, USA; Omega Optics Inc, 8500 Shoal Creek Blvd, Austin, TX, 78759, USA., Huang HC; Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan, ROC., Tu LW; Department of Physics and Center of Crystal Research, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan, ROC; Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan, ROC., Chen QY; Department of Physics and Center of Crystal Research, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan, ROC., Dalir H; Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78758, USA; Omega Optics Inc, 8500 Shoal Creek Blvd, Austin, TX, 78759, USA., Krainak MA; NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA., Chen RT; Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78758, USA; Omega Optics Inc, 8500 Shoal Creek Blvd, Austin, TX, 78759, USA. Electronic address: chen@ece.utexas.edu.
Jazyk: angličtina
Zdroj: Biosensors & bioelectronics [Biosens Bioelectron] 2019 Sep 15; Vol. 141, pp. 111396. Date of Electronic Publication: 2019 Jun 01.
DOI: 10.1016/j.bios.2019.111396
Abstrakt: Mode volume overlap factor is one of the parameters determining the sensitivity of a sensor. In past decades, many approaches have been proposed to increase the mode volume overlap. As the increased mode volume overlap factor results in reduced mode confinement, the maximum value is ultimately determined by the micro- and nano-structure of the refractive index distribution of the sensing devices. Due to the asymmetric index profile along the vertical direction on silicon-on-insulator platform, further increasing the sensitivity of subwavelength grating metamaterial (SGM) waveguide based sensors is challenging. In this paper, we propose and demonstrate pedestaled SGM which reduces the asymmetricity and thus allows further increasing the interaction between optical field and analytes. The pedestal structure can be readily formed by a controlled undercut etching. Both theoretical analysis and experimental demonstration show a significant improvement of sensitivity. The bulk sensitivity and surface sensitivity are improved by 28.8% and 1000 times, respectively. The detection of streptavidin at a low concentration of 0.1 ng/mL (∼1.67 pM) is also demonstrated through real-time monitoring of the resonance shift. A ∼400 fM streptavidin limit of detection is expected with a 0.01nm resolution spectrum analyzer based on the real-time measurement of streptavidin detection results from two-site binding model fitting.
(Copyright © 2019 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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