Photoemission electron microscopy as a tool for the investigation of optical near fields -: art. no. 047601
Photoemission electron microscopy as a tool for the investigation of optical near fields -: art. no. 047601
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DOI：
10.1103/physrevlett.95.047601
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发表时间：
2005-07-22
影响因子：
8.6
通讯作者：
Kreiter, M
中科院分区：
文献类型：
--
作者：
Cinchetti, M;Gloskovskii, A;Kreiter, M
使用光发射电子显微镜对从沉积在Si衬底（具有其原生氧化物SiOx）上的特别定制的Ag纳米颗粒光发射的电子进行成像。通过分别用Hg UV灯（光子能量截止h ω（UV）=5.0 eV，波长λ（UV）=250 nm）和用Ti：蓝宝石飞秒激光器（h ω（I）=3.1 eV，λ（I）=400 nm，脉冲宽度低于200 fs）照射来诱导光发射。虽然在高于银等离子体激元频率的能量下照射时观察到来自金属的均匀光电子发射，但在较低的光子能量下，发射局限于结构的尖端。这被解释为一个签名的局部电场，因此提供了一个工具来映射的光学近场与发射电子显微镜的分辨率。
Photoemission electron microscopy was used to image the electrons photoemitted from specially tailored Ag nanoparticles deposited on a Si substrate (with its native oxide SiOx). Photoemission was induced by illumination with a Hg UV lamp (photon energy cutoff h omega(UV)=5.0 eV, wavelength lambda(UV)=250 nm) and with a Ti:sapphire femtosecond laser (h omega(l)=3.1 eV, lambda(l)=400 nm, pulse width below 200 fs), respectively. While homogeneous photoelectron emission from the metal is observed upon illumination at energies above the silver plasmon frequency, at lower photon energies the emission is localized at tips of the structure. This is interpreted as a signature of the local electrical field therefore providing a tool to map the optical near field with the resolution of emission electron microscopy.