Demonstration of an ultrasensitive refractive-index plasmonic sensor by enabling its quadrupole resonance in phase interrogation

Hsin Cheng Lee, Chung Tien Li, How Foo Chen, Ta Jen Yen

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

We present an ultrasensitive plasmonic sensing system by introducing a nanostructured X-shaped plasmonic sensor (XPS) and measuring its localized optical properties in phase interrogation. Our tailored XPS exhibits two major resonant modes of a low-order dipole and a high-order quadrupole, between which the quadrupole resonance allows an ultrahigh sensitivity, due to its higher quality factor. Furthermore, we design an in-house common-path phase-interrogation system, in contrast to conventional wavelength-interrogation methods, to achieve greater sensing capability. The experimental measurement shows that the sensing resolution of the XPS reaches 1.15 × 10-6 RIU, not only two orders of magnitude greater than the result of the controlled extinction measurement (i.e., 9.90 × 10-5 RIU), but also superior than current reported plasmonic sensors.

Original languageEnglish
Pages (from-to)5152-5155
Number of pages4
JournalOptics Letters
Volume40
Issue number22
DOIs
StatePublished - 15 Nov 2015

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