Laser THz emission nanoscopy and THz nanoscopy
Laser THz emission nanoscopy and THz nanoscopy
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DOI：
10.1364/oe.382130
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发表时间：
2020-06-22
期刊：
影响因子：
3.8
通讯作者：
Klarskov, Pernille
中科院分区：
文献类型：
--
作者：
Pizzuto, Angela;Mittleman, Daniel M.;Klarskov, Pernille
我们提出了一个实验和理论比较两种不同的散射型扫描近场光学显微镜（S-SNOM）为基础的技术在太赫兹制度;纳米级反射型太赫兹时域光谱（太赫兹纳米）和纳米级激光太赫兹发射显微镜，或激光太赫兹发射纳米显微镜（LTEN）。我们表明，互补信息的材料的电荷载流子可以从这些技术时，背靠背。对于在轻p掺杂InAs样品上进行的THz纳米显微镜和LTEN成像的特定情况，我们能够记录具有解调到尖端振荡频率的第6和第10谐波的检测器信号分量的波形，并测量THz近场限制低至11 nm。提出了一种用于确定导电探针的近场区域中的增强电场的空间限制的计算方法，其表现出有效的“尖端锐化”的情况下，纳米级LTEN由于太赫兹产生机制的替代几何形状和光学非线性。最后，我们证明了有限偶极子模型（FDM）在预测宽带散射太赫兹电场的效用，并提出了第一次使用该模型预测LTEN的近场响应。(C)根据OSA开放获取出版协议的条款，2020年美国光学学会
We present an experimental and theoretical comparison of two different scattering-type scanning near-field optical microscopy (s-SNOM) based techniques in the terahertz regime; nanoscale reflection-type terahertz time-domain spectroscopy (THz nanoscopy) and nanoscale laser terahertz emission microscopy, or laser terahertz emission nanoscopy (LTEN). We show that complementary information regarding a material's charge carriers can be gained from these techniques when employed back-to-back. For the specific case of THz nanoscopy and LTEN imaging performed on a lightly p-doped InAs sample, we were able to record waveforms with detector signal components demodulated up to the 6th and the 10th harmonic of the tip oscillation frequency, and measure a THz near-field confinement down to 11 nm. A computational approach for determining the spatial confinement of the enhanced electric field in the near-field region of the conductive probe is presented, which manifests an effective "tip sharpening" in the case of nanoscale LTEN due to the alternative geometry and optical nonlinearity of the THz generation mechanism. Finally, we demonstrate the utility of the finite dipole model (FDM) in predicting the broadband scattered THz electric field, and present the first use of this model for predicting a near-field response from LTEN. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement