Ultrahigh Figure-of-Merit in Metal-Insulator-Metal Magnetoplasmonic Sensors Using Low Loss Magneto-optical Oxide Thin Films

TitleUltrahigh Figure-of-Merit in Metal-Insulator-Metal Magnetoplasmonic Sensors Using Low Loss Magneto-optical Oxide Thin Films
Publication TypeJournal Article
Year of Publication2017
AuthorsQin, J, Zhang, Y, Liang, X, Liu, C, Wang, C, Kang, T, Lu, H, Zhang, L, Zhou, P, Wang, X, Peng, B, Hu, J, Deng, L, Bi, L
JournalAcs Photonics
Volume4
Issue6
Pagination1403 - 1412
Date Published2017/06//
ISBN Number2330-4022
Keywordsbiosensor, biosensors, enhancement, fano resonances, iron-garnet films, label-free detection, magnetoplasmonic, metal-insulator-metal, metamaterials, optical-properties, sensing applications, surface-plasmon-resonance, transverse magneto-optical Kerr effect, wave-guide
Abstract

Achieving high figure-of-merit (defined as the ratio between refractive index sensitivity and spectral line width) in surface plasmon sensors is a fundamental quest for ultrasensitive chemical and biomedical sensing applications. Due to ohmic loss of plasmonic metal thin films, the theoretical limit of figure-of-merit is around 54 RIU-' (refractive index unit) for Au-based plasmonic sensors at 650 nm wavelength. Here, we report a way to significantly boost the device figure-of-merit by incorporating low loss magneto optical oxides in a novel metal insulator metal magnetoplasmonic sensor. Our theoretical analysis shows that a record high figure-of-merit of 39600 RIU-1 can be achieved in a simple multilayer thin film sensor device at the wavelength of 650 nm, which well exceeds that of conventional surface plasmon resonance sensors at the same wavelength. A high figure-of-merit of 964 +/- 150 RIU-1 is demonstrated experimentally at 650 nm, 17.8X higher than the theoretical limit of Au surface plasmon resonance sensors at the same wavelength. The high figure-of-merit originates from strong coupling between the magneto-optical waveguide mode and the surface plasmon resonance mode causing a narrow transverse magneto-optical Kerr effect spectrum with Fano line shape at resonant excitation conditions. The limit-of detection reaches 4.13 x 10(-6) RIU, which is 16X higher compared to a standard Au SPR sensor measured on the same setup. Biomedical sensing using bovine serum albumin solutions and biotin streptavidin interaction demonstrate excellent sensing performance and chemical stability of such metal insulator metal magnetoplasmonic sensors.

Short TitleACS Photonics