Interfering Plasmons in Coupled Nanoresonators to Boost Light Localization and SERS.

Change log
Zheng, Xuezhi 
Demetriadou, Angela  ORCID logo
Martínez, Alejandro  ORCID logo

Plasmonic self-assembled nanocavities are ideal platforms for extreme light localization as they deliver mode volumes of <50 nm3. Here we show that high-order plasmonic modes within additional micrometer-scale resonators surrounding each nanocavity can boost light localization to intensity enhancements >105. Plasmon interference in these hybrid microresonator nanocavities produces surface-enhanced Raman scattering (SERS) signals many-fold larger than in the bare plasmonic constructs. These now allow remote access to molecules inside the ultrathin gaps, avoiding direct irradiation and thus preventing molecular damage. Combining subnanometer gaps with micrometer-scale resonators places a high computational demand on simulations, so a generalized boundary element method (BEM) solver is developed which requires 100-fold less computational resources to characterize these systems. Our results on extreme near-field enhancement open new potential for single-molecule photonic circuits, mid-infrared detectors, and remote spectroscopy.

Nanocavity, SERS, field enhancement, nano-optics, near-field, plasmon interference, remote excitation
Journal Title
Nano Lett
Conference Name
Journal ISSN
Volume Title
American Chemical Society (ACS)
All rights reserved
Engineering and Physical Sciences Research Council (EP/L015978/1)
Engineering and Physical Sciences Research Council (EP/L027151/1)
Engineering and Physical Sciences Research Council (EP/S022953/1)
Engineering and Physical Sciences Research Council (EP/P029426/1)
Engineering and Physical Sciences Research Council (EP/R020965/1)
European Commission Horizon 2020 (H2020) Future and Emerging Technologies (FET) (829067)
European Commission Horizon 2020 (H2020) Research Infrastructures (RI) (861950)
European Commission Horizon 2020 (H2020) ERC (883703)
Engineering and Physical Sciences Research Council (EP/G060649/1)
We acknowledge support from European Research Council (ERC) under Horizon 2020 research and innovation programme THOR (Grant Agreement No. 829067), POSEIDON (Grant Agreement No. 861950) and PICOFORCE (Grant Agreement No. 883703). We acknowledge funding from the EPSRC (Cambridge NanoDTC EP/ L015978/1, EP/L027151/1, EP/S022953/1, EP/P029426/1, and EP/R020965/1). R.C. acknowledges support from Trinity College, University of Cambridge. A.D. acknowledges support from the Royal Society University Research Fellowship URF/R1/180097 and Royal Society Research Fellows Enhancement Award RGF/EA/181038.
Is supplemented by: