Plasmonic Near-Electric Field Enhancement Effects in Ultrafast Photoelectron Emission: Correlated Spatial and Laser Polarization Microscopy Studies of Individual Ag Nanocubes
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- 作者：Andrej Grubisic ; Emilie Ringe ; Claire M. Cobley ; Younan Xia ; Laurence D. Marks ; Richard P. Van Duyne ; David J. Nesbitt
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：September 12, 2012
- 年：2012
- 卷：12
- 期：9
- 页码：4823-4829
- 全文大小：466K
- 年卷期：v.12,no.9(September 12, 2012)
- ISSN：1530-6992
文摘
Electron emission from single, supported Ag nanocubes excited with ultrafast laser pulses (位 = 800 nm) is studied via spatial and polarization correlated (i) dark field scattering microscopy (DFM), (ii) scanning photoionization microscopy (SPIM), and (iii) high-resolution transmission electron microscopy (HRTEM). Laser-induced electron emission is found to peak for laser polarization aligned with cube diagonals, suggesting the critical influence of plasmonic near-field enhancement of the incident electric field on the overall electron yield. For laser pulses with photon energy below the metal work function, coherent multiphoton photoelectron emission (MPPE) is identified as the most probable mechanism responsible for electron emission from Ag nanocubes and likely metal nanoparticles/surfaces in general.