title: A multi-functional plasmonic biosensor.
abstract: We present a coupler-free, multi-mode refractive index sensor based on nanostructured split ring resonators (SRRs). The fabricated SRR structures exhibit multiple reflectance peaks, whose spectral positions are sensitive to local dielectric environment and can be quantitatively described by our standing-wave plasmonic resonance model, providing a design rule for this multi-mode refractive-index (MMRI) sensor. We further manifest that the lower-order modes possess greater sensitivity associated with stronger localized electromagnetic field leading to shorter detection lengths within five hundreds nanometers, while the higher-order modes present mediate sensitivity with micron-scale detection lengths to allow intracellular bio-events detection. These unique merits enable the SRR-based sensor a multi-functional biosensor and a potential label-free imaging device.
authors.affiliation: Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China.
authors.forename: Yun-Tzu
authors.initials: YT
authors.lastname: Chang
authors.forename: Yueh-Chun
authors.initials: YC
authors.lastname: Lai
authors.forename: Chung-Tien
authors.initials: CT
authors.lastname: Li
authors.forename: Cheng-Kuang
authors.initials: CK
authors.lastname: Chen
authors.forename: Ta-Jen
authors.initials: TJ
authors.lastname: Yen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D013057:Spectrum Analysis