Discrimination of Bulk and Surface Refractive Index Change in Plasmonic Sensors with Narrow Bandwidth Resonance Combs
| Autor: | Xuejun Zhang, Fu Liu, Jacques Albert, Tuan Guo, Anatoli Ianoul, Kaiwei Li |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Bioengineering 02 engineering and technology engineering.material 01 natural sciences Fiber Bragg grating Coating Fiber Optic Technology Surface layer Surface plasmon resonance Instrumentation Plasmon Fluid Flow and Transfer Processes business.industry Process Chemistry and Technology 010401 analytical chemistry Resonance Surface Plasmon Resonance 021001 nanoscience & nanotechnology Cladding mode 0104 chemical sciences Refractometry 13. Climate action engineering Optoelectronics Gold 0210 nano-technology business Refractive index |
| Zdroj: | ACS Sensors. 6:3013-3023 |
| ISSN: | 2379-3694 |
| DOI: | 10.1021/acssensors.1c00906 |
| Popis: | A method to enable surface plasmon resonance (SPR) sensors to discriminate between bulk and surface-localized refractive index changes is demonstrated with modified gold-coated tilted fiber Bragg grating SPR sensors (TFBG-SPR). Without this capability, all high-resolution SPR sensors should be using reference channels and strict temperature control to prevent the contamination of the desired detection of surface-localized chemical or binding events by drift of the refractive index of the medium, in which the experiment is carried out. The very fine comb of high-quality-factor resonances of a TFBG-SPR device coupled to the large differential sensitivity of some of the resonances to various perturbations is used to measure unambiguously the refractive index changes within a surface layer thinner than 25 nm from those of the bulk surrounding. The enabling modification of the conventional TFBG-SPR is a reduction of the gold coating from its optimum value near 50-30 nm: at this lower thickness, a surface plasmon wave can still be excited by a limited number of cladding mode resonances, but at the same time, the metal is thin enough to allow modes away from the SPR to tunnel across the metal and probe the bulk RI value. Measurements and simulations of the deposition of a self-assembled monolayer of 1-dodecanethiol in ethanol show that the bulk refractive index changes as small as 0.0004 can be distinguished from the formation of a 1 nm thick coating on the surface of the fiber. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|