Green light stimulates terahertz emission from mesocrystal microspheres.
Green light stimulates terahertz emission from mesocrystal microspheres.
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DOI：
10.1038/nnano.2010.264
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发表时间：
2011-02
影响因子：
38.3
通讯作者：
X. Wu;S. Xiong;Z. Liu;J. Chen;J. Shen;T. H. Li;P. Wu;P. Chu
中科院分区：
文献类型：
--
作者：
X. Wu;S. Xiong;Z. Liu;J. Chen;J. Shen;T. H. Li;P. Wu;P. Chu
高效太赫兹辐射源的发现已在成像应用中得到利用，而开发纳米级太赫兹源可能会带来更多应用。带电纳米结构的高频机械振动可导致辐射发射，在交变电场的影响下，ZnO 纳米带可观察到数百千赫兹频率的振动。在这里，我们观察到由连续绿光波长激光激发的核壳 ZnO 介晶微球在~0.36 THz 处的机械共振和辐射发射。我们发现~0.016%的入射功率转化为太赫兹辐射，这对应于~33%的量子效率，使得ZnO微球与现有的太赫兹发射材料具有竞争力。机械共振和辐射源于构成微球壳的六方氧化锌纳米片的相干光致振动。 ZnO 微球是通过非经典的自组织结晶过程形成的，代表了纳米级太赫兹辐射的直接途径。
The discovery of efficient sources of terahertz radiation has been exploited in imaging applications, and developing a nanoscale terahertz source could lead to additional applications. High-frequency mechanical vibrations of charged nanostructures can lead to radiative emission, and vibrations at frequencies of hundreds of kilohertz have been observed from a ZnO nanobelt under the influence of an alternating electric field. Here, we observe mechanical resonance and radiative emission at ∼0.36 THz from core–shell ZnO mesocrystal microspheres excited by a continuous green-wavelength laser. We find that ∼0.016% of the incident power is converted into terahertz radiation, which corresponds to a quantum efficiency of ∼33%, making the ZnO microspheres competitive with existing terahertz-emitting materials,. The mechanical resonance and radiation stem from the coherent photo-induced vibration of the hexagonal ZnO nanoplates that make up the microsphere shells. The ZnO microspheres are formed by means of a nonclassical, self-organized crystallization process,,, and represent a straightforward route to terahertz radiation at the nanoscale.