Visualization of the spatial-temporal evolution of continuous electromagnetic waves in the terahertz range based on photonics technology
Visualization of the spatial-temporal evolution of continuous electromagnetic waves in the terahertz range based on photonics technology
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DOI：
10.1364/optica.1.000365
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发表时间：
2014-12-20
期刊：
影响因子：
10.4
通讯作者：
Nagatsuma, Tadao
中科院分区：
文献类型：
--
作者：
Hisatake, Shintaro;Hai Huy Nguyen Pham;Nagatsuma, Tadao
太赫兹（THz）波段连续波场演化的高相位和空间分辨率可视化是研究非衍射、自重构和涡旋等独特光束物理动力学的新途径。由于近场可视化可以揭示器件的动力学，因此它也可用于诊断THz器件。在这里，我们展示了可视化的自由传播的连续太赫兹波的空间时间演化适应非偏振电光（EO）检测技术的自外差系统。太赫兹波（125 GHz，.λ = 2.4毫米，650 μ W）辐射的喇叭天线的同时，精确地测量在自外差系统，其中两个频率失谐的自由运行的激光器都用于产生（光混频）和EO检测太赫兹波。非偏振光电探测技术解决了传统偏振光电探测技术的一个固有问题，即用于光电探测的光本振信号的偏振态的波动会使测量的灵敏度急剧变化。其结果是，场的演变可以可视化的最大信噪比为27 dB和相位分辨率为2 π/78 rad（80 mrad），通过反复扫描光纤安装EO晶体（ZnTe）在自由空间。(C)2014年美国光学学会
Visualization of the field evolution of the continuous waves in the terahertz (THz) range with high phase and spatial resolution is a new approach to the study of the physical dynamics of unique beams, such as nondiffractive, self-reconstructing, and vortex beams. As near-field visualization can reveal device dynamics, it is also useful for diagnosing the THz devices. Here, we demonstrate the visualization of the spatial temporal evolution of freely propagating continuous THz waves by adapting the nonpolarimetric electro-optic (EO) detection technique to the self-heterodyne system. The amplitude and phase of a THz wave (125 GHz,. lambda = 2.4 mm, 650 mu W) radiated from a horn antenna were simultaneously and precisely measured in the self-heterodyne system, in which two frequency-detuned free-running lasers were used both for the generation (photomixing) and EO detection of THz waves. The nonpolarimetric EO detection technique has solved an intrinsic problem of the conventional polarimetric EO detection technique, in which the sensitivity of the measurements can be changed drastically by the fluctuation of the polarization state of the optical local oscillator signal for the EO detection. As a result, field evolution could be visualized with a maximum signal-to-noise ratio of 27 dB and a phase resolution of 2 pi/78 rad (80 mrad), by scanning an optical fiber-mounted EO crystal (ZnTe) in a free space repeatedly. (C) 2014 Optical Society of America