Surface plasmon resonance optical cavity enhanced refractive index sensing

Abstract

We report on a method for surface plasmon resonance (SPR) refractive index sensing based on direct time-domain measurements. An optical resonator is built around an SPR sensor, and its photon lifetime is measured as a function of loss induced by refractive index variations. The method does not rely on any spectroscopic analysis or direct intensity measurement. Time-domain measurements are practically immune to light intensity fluctuations and thus lead to high resolution. A proof of concept experiment is carried out in which a sensor response to liquid samples of different refractive indices is measured. A refractive index resolution of the current system, extrapolated from the reproducibility of cavity-decay time determinations over 133 s, is found to be about 10(-5) RIU. The possibility of long-term averaging suggests that measurements with a resolution better than 10(-7) RIU/√Hz are within reach.

Liquid refractive index sensing independent of opacity using an optofluidic diffraction sensor

“…In recent decades, many optical sensors for fluid and biofluid sensing have been developed due to their high accuracy, wide dynamic range, electrical passiveness, repeatability and nonintrusiveness [3], and many of them are specifically for RI measurement. RI sensing schemes include laser interferometry [4], capillary [5], photonic crystals [6], surface plasmon resonance [7], optical fibers [8] and diffraction gratings [9][10][11]. Most of those approaches are for RI sensing only and require sophisticated facilities including lens, beam splitter, spectrometers and so on.…”

Nanoporous Gold Films Prepared by a Combination of Sputtering and Dealloying for Trace Detection of Benzo[a]pyrene Based on Surface Plasmon Resonance Spectroscopy

“…These characteristics of BaP give us the idea that compared with a gravimetric sensor such as quartz crystal microbalance (QCM), a refractometric sensor would be more suitable for detection of trace BaP in air and water. It is well known that surface plasmon resonance (SPR) sensors are refractive-index-sensitive devices with label-free detection capability [14,15]. However, a conventional SPR sensor with a dense gold film enables detection of large biomolecules, and its sensitivity is not sufficient for direct detection of small molecules [16].…”

Highly sensitive biochemical sensor comprising rectangular nanometal arrays

“…The formation of such a wave at the metal-analyte interface enables PSPR sensors to be highly sensitive to changes in the refractive index of an analyte. Therefore, PSPR sensors have been extensively applied in several fields including biology, genetic engineering, and biochemistry [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The second category comprises localized surface plasmon resonance (LSPR) sensors that have no propagation capability.…”