Direct molecular-level near-field plasmon and temperature assessment in a single plasmonic hotspot  

作　　者：Marie Richard-Lacroix Volker Deckert 

机构地区：[1]Leibniz Institute of Photonic Technology(IPHT),Albert-Einstein-Strasse 9,D-07745 Jena,Germany [2]Institute of Physical Chemistry and Abbe Center of Photonics,University of Jena,Helmholtzweg 4,D-07743 Jena,Germany

出　　处：《Light(Science & Applications)》2020年第1期1673-1685,共13页光（科学与应用)（英文版）

基　　金：the support via the German Research Foundation DFG(CRC 1375 NOA);the financial support of the NSERC and the DFG(Project number 364549901-TRR 234 CataLight(C1)).

摘　　要：Tip-enhanced Raman spectroscopy(TERS)is currently widely recognized as an essential but still emergent technique for exploring the nanoscale.However,our lack of comprehension of crucial parameters still limits its potential as a user-friendly analytical tool.The tip’s surface plasmon resonance,heating due to near-field temperature rise,and spatial resolution are undoubtedly three challenging experimental parameters to unravel.However,they are also the most fundamentally relevant parameters to explore,because they ultimately influence the state of the investigated molecule and consequently the probed signal.Here we propose a straightforward and purely experimental method to access quantitative information of the plasmon resonance and near-field temperature experienced exclusively by the molecules directly contributing to the TERS signal.The detailed near-field optical response,both at the molecular level and as a function of time,is evaluated using standard TERS experimental equipment by simultaneously probing the Stokes and anti-Stokes spectral intensities.Self-assembled 16-mercaptohexadodecanoic acid monolayers covalently bond to an ultra-flat gold surface were used as a demonstrator.Observation of blinking lines in the spectra also provides crucial information on the lateral resolution and indication of atomic-scale thermally induced morphological changes of the tip during the experiment.This study provides access to unprecedented molecular-level information on physical parameters that crucially affect experiments under TERS conditions.The study thereby improves the usability of TERS in day-to-day operation.The obtained information is of central importance for any experimental plasmonic investigation and for the application of TERS in the field of nanoscale thermometry.

关 键 词：STRAIGHT purely thereby 

分 类 号：O53[理学—等离子体物理]