基于近零介电常数材料的宽带太赫兹波产生
Broadband terahertz wave generation from an epsilon-near-zero material.
作者信息
Jia Wenhe, Liu Meng, Lu Yongchang, Feng Xi, Wang Qingwei, Zhang Xueqian, Ni Yibo, Hu Futai, Gong Mali, Xu Xinlong, Huang Yuanyuan, Zhang Weili, Yang Yuanmu, Han Jiaguang
机构信息
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
Center for THz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, 300072, China.
出版信息
Light Sci Appl. 2021 Jan 7;10(1):11. doi: 10.1038/s41377-020-00452-y.
Broadband light sources emitting in the terahertz spectral range are highly desired for applications such as noninvasive imaging and spectroscopy. Conventionally, THz pulses are generated by optical rectification in bulk nonlinear crystals with millimetre thickness, with the bandwidth limited by the phase-matching condition. Here we demonstrate broadband THz emission via surface optical rectification from a simple, commercially available 19 nm-thick indium tin oxide (ITO) thin film. We show an enhancement of the generated THz signal when the pump laser is tuned around the epsilon-near-zero (ENZ) region of ITO due to the pump laser field enhancement associated with the ENZ effect. The bandwidth of the THz signal generated from the ITO film can be over 3 THz, unrestricted by the phase-matching condition. This work offers a new possibility for broadband THz generation in a subwavelength thin film made of an ENZ material, with emerging physics not found in existing nonlinear crystals.
太赫兹光谱范围内发射的宽带光源对于非侵入性成像和光谱学等应用非常有需求。传统上，太赫兹脉冲是通过毫米厚的块状非线性晶体中的光整流产生的，其带宽受相位匹配条件限制。在此，我们展示了通过表面光整流从一种简单的、市售的19纳米厚氧化铟锡（ITO）薄膜产生宽带太赫兹辐射。我们发现，当泵浦激光调谐到ITO的近零介电常数（ENZ）区域附近时，由于与ENZ效应相关的泵浦激光场增强，所产生的太赫兹信号得到增强。从ITO薄膜产生的太赫兹信号带宽可以超过3太赫兹，不受相位匹配条件限制。这项工作为在由ENZ材料制成的亚波长薄膜中产生宽带太赫兹提供了新的可能性，具有现有非线性晶体中未发现的新物理现象。
Zotero 插件