LSPR Based Double Peak Double Plasmonic Layered Bent Core PCF-SPR Sensor for Ultra-Broadband Dual Peak Sensing
Mohammad Rakibul Islam, A. N. M. Iftekher, Mariea Sharaf Anzum, Muntaha Rahman, Sadia Siraz
Abstract
Through this paper, a sensor based on localized surface plasmon resonance (LSPR) with simultaneous use of gold and aluminium doped zinc oxide (AZO) as plasmonic materials has been proffered. Incorporating these two different plasmonic materials has brought out a unique dispersion relation where double resonance peaks have been detected. After optimizing structural parameters, the simulated results have distinguished that this sensor exhibits maximum amplitude sensitivity of 8485.2 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> along with maximum wavelength sensitivity of 46300 nm/RIU in the direction of y-polarization whenever AZO is used as the middle plasmonic material. Furthermore, the sensor obtains a maximum amplitude resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.18\times 10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−6</sup> RIU and a maximum wavelength resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.16\times 10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−6</sup> RIU. A higher figure of merit of 2923.2 can also be obtained, indicating higher detection accuracy through this sensor and maximum linearity of R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.99312. Moreover, the proffered sensor has shown its ability to detect unspecified analytes with a refracting index in the maximum wide range of 1.27 to 1.45. Apart from these sensing parameters obtained from analyzing the double peaks separately, a new sensing parameter called double peak shift sensitivity has been introduced in this study. This sensor displays a maximum double peak sensitivity of 4400 nm/RIU for x-polarization mode and 16500 nm/RIU for y-polarization mode considering the double peaks together for two adjacent RIs. Due to these diverse features, the proposed design can open the doors to notable developments in a wide range of analytes and biological organic chemicals detection with ultra-high accuracy and broadband applications.