Near-unity Raman β-factor of surface-enhanced Raman scattering in a waveguide

Fu，Ming1; Mota，Mónica P.d.S.P.1; Xiao，Xiaofei1; Jacassi，Andrea1; Güsken，Nicholas A.1,2; Chen，Yuxin1; Xiao，Huaifeng1; Li，Yi1,3; Riaz，Ahad1; Maier，Stefan A.1,4,5; Oulton，Rupert F.1

2022

10.1038/s41565-022-01232-y

Nature Nanotechnology   Impact Factor & Quartile

1748-3387

1748-3395

The Raman scattering of light by molecular vibrations is a powerful technique to fingerprint molecules through their internal bonds and symmetries. Since Raman scattering is weak, methods to enhance, direct and harness it are highly desirable, and this has been achieved using optical cavities, waveguides and surface-enhanced Raman scattering (SERS). Although SERS offers dramatic enhancements by localizing light within vanishingly small hot-spots in metallic nanostructures, these tiny interaction volumes are only sensitive to a few molecules, yielding weak signals. Here we show that SERS from 4-aminothiophenol molecules bonded to a plasmonic gap waveguide is directed into a single mode with >99% efficiency. Although sacrificing a confinement dimension, we find a SERS enhancement of ~10 times across a broad spectral range enabled by the waveguide’s larger sensing volume and non-resonant waveguide mode. Remarkably, this waveguide SERS is bright enough to image Raman transport across the waveguides, highlighting the role of nanofocusing and the Purcell effect. By analogy to the β-factor from laser physics, the near-unity Raman β-factor we observe exposes the SERS technique to alternative routes for controlling Raman scattering. The ability of waveguide SERS to direct Raman scattering is relevant to Raman sensors based on integrated photonics with applications in gas sensing and biosensing.

SCI

English

NI Journal Papers

Others

EPSRC Reactive Plasmonics Programme[EP/M013812/1] ; EPSRC Catalysis Plasmonics Programme[EP/W017075/1] ; Leverhulme Trust[RPG-2016-064] ; European Union's Horizon 2020 research and innovation programme under a Marie Sklodowska-Curie Fellowship[844591] ; German National Academy of Sciences Leopoldina[LPDS2020-12]

Science & Technology - Other Topics ; Materials Science

Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000874394200002

NATURE PORTFOLIO

2-s2.0-85140822576

Scopus

1.Blackett Laboratory,Imperial College London,London,United Kingdom
2.Geballe Laboratory for Advanced Materials,Stanford University,Stanford,United States
3.School of Microelectronics,MOE Engineering Research Center of Integrated Circuits for Next Generation Communications,Southern University of Science and Technology,Shenzhen,China
4.School of Physics and Astronomy,Monash University,Clayton,Australia
5.Chair in Hybrid Nanosystems,Nanoinstitute Munich,Faculty of Physics,Ludwig-Maximilians-Universität München,Munich,Germany

Fu，Ming,Mota，Mónica P.d.S.P.,Xiao，Xiaofei,et al. Near-unity Raman β-factor of surface-enhanced Raman scattering in a waveguide[J]. Nature Nanotechnology,2022.

Fu，Ming.,Mota，Mónica P.d.S.P..,Xiao，Xiaofei.,Jacassi，Andrea.,Güsken，Nicholas A..,...&Oulton，Rupert F..(2022).Near-unity Raman β-factor of surface-enhanced Raman scattering in a waveguide.Nature Nanotechnology.

Fu，Ming,et al."Near-unity Raman β-factor of surface-enhanced Raman scattering in a waveguide".Nature Nanotechnology (2022).