Giant mid-IR resonant coupling to molecular vibrations in sub-nm gaps of plasmonic multilayer metafilms  

作　　者：Rakesh Arul David-Benjamin Grys Rohit Chikkaraddy Niclas S.Mueller Angelos Xomalis Ermanno Miele Tijmen Geuser Jeremy J.Baumberg 

机构地区：[1]NanoPhotonics Centre,Cavendish Laboratory,Department of Physics,JJ Thompson Avenue,University of Cambridge,Cambridge CB30HE,United Kingdom [2]The Faraday Institution,Quad One,Harwell Science and Innovation Campus,Didcot,United Kingdom

出　　处：《Light(Science & Applications)》2022年第10期2476-2484,共9页光（科学与应用)（英文版）

基　　金：We acknowledge support from European Research Council(ERC)under Horizon 2020 research and innovation programme THOR(Grant Agreement No.829067);PICOFORCE(Grant Agreement No.883703).

摘　　要：Nanomaterials capable of confining light are desirable for enhancing spectroscopies such as Raman scattering,infrared absorption,and nonlinear optical processes.Plasmonic superlattices have shown the ability to host collective resonances in the mid-infrared,but require stringent fabrication processes to create well-ordered structures.Here,we demonstrate how short-range-ordered Au nanoparticle multilayers on a mirror,self-assembled by a sub-nm molecular spacer,support collective plasmon-polariton resonances in the visible and infrared,continuously tunable beyond 11 pm by simply varying the nanoparticle size and number of layers.The resulting molecule-plasmon system approaches vibrational strong coupling,and displays giant Fano dip strengths,SEIRA enhancement factors~106,light-matter coupling strengths g~100 cm-1,Purcell factors~106,and mode volume compression factors~108.The collectiive plasmon-polariton mode is highly robust to nanoparticle vacancy disorder and is sustained by the consistent gap size defined by the molecular spacer.Structural disorder efficiently couples light into the gaps between the multilayers and mirror,enabling Raman and infrared sensing of sub-picolitre sample volumes.

关 键 词：coupling COLLECTIVE MIRROR 

分 类 号：O53[理学—等离子体物理]