title: Raman scattering enhanced within the plasmonic gap between an isolated Ag triangular nanoplate and Ag film.
abstract: Enhanced electromagnetic field in the tiny gaps between metallic nanostructures holds great promise in optical applications. Herein, we report novel out-of-plane nanogaps composed of micrometer-sized Ag triangular nanoplates (AgTN) on Ag films. Notably, the new coupled plasmonic structure can dramatically enhance the surface-enhanced Raman scattering (SERS) by visible laser excitation, although the micrometer-sized AgTN has localized plasmon resonance at infrared wavelength. This enhancement is derived from the gap plasmon polariton between the AgTN and Ag film, which is excited via the antenna effect of the corner and edge of the AgTN. Systematic SERS studies indicated that the plasmon enhancement was on the order of corner > edge > face. These results were further verified by theoretical simulations. Our device paves the way for rational design of sensitive SERS substrates by judiciously choosing appropriate nanoparticles and optimizing the gap distance.
authors.affiliation: Department of Optics and Optical Engineering & Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Kuanguo
authors.initials: K
authors.lastname: Li
authors.forename: Kang
authors.initials: K
authors.lastname: Jiang
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Mao
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Lu
authors.forename: Pei
authors.initials: P
authors.lastname: Wang