A plasmonic refractive index sensor with an ultrabroad dynamic sensing range

Yu Chieh Cheng, Ya Ju Chang, Yu Ching Chuang, Bo Zhi Huang, Chii Chang Chen

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Refractive index sensors based on surface plasmon resonance (SPR) promise to deliver high sensitivities. However, these sensitivities depend on the derivative of the monitored SPR parameters near resonance, so this dependency leads to a relatively narrow detection range for refractive index changes. Herein, we introduce an idea to improve the detection range refractive index through a high-contrast-index curved waveguide surrounded with an outer gold ring. The proposed detection technique, based on the output power measurement of the curved waveguide, offers a linear response over an ultrabroad range of the refractive index for a surrounding medium from n = 1 to 2.36. Meanwhile, an theoretically ultrahigh refractive index resolution (RIU) of 4.53 × 10 −10 could be accessible for such a broad testing range, available for both gas and aqueous chemical sample refractive indices Furthermore, the power detection approach enables an integrated photodetector for a lab-on-chip sensor platform, revealing a high potential for a multifunctional, compact, and highly sensitive sensor-on-chip device.

Original languageEnglish
Article number5134
JournalScientific Reports
Issue number1
StatePublished - 1 Dec 2019


Dive into the research topics of 'A plasmonic refractive index sensor with an ultrabroad dynamic sensing range'. Together they form a unique fingerprint.

Cite this