Nanoscopic Spotlight in a Spindle Semiconductor Nanowire
Nanoscopic Spotlight in a Spindle Semiconductor Nanowire
复制标题
主轴半导体纳米线中的纳米聚光灯
DOI：
10.1021/acsnano.8b08147
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发表时间：
2019
期刊：
影响因子：
17.1
通讯作者：
Wang Chengxin
中科院分区：
文献类型：
--
作者：
Sun Yong;Xie Xiangsheng;Chen Yongzhu;Sun Bo;Wang Chengxin
从理论上讲，无论纳米线有多薄，它都可以以倏逝场的形式传输光。然而，实际上，当纳米线明显薄于λ/2时，由复杂耗散引起的低传播效率使得难以实现光传输。因此，这种规模的纳米线光子学研究是有限的。在此，光传播是在一个非常薄的纺锤形纳米线（直径低于70 nm），其中形成了纳米级的聚光灯。该纳米线在横向尺寸上输出最大发射，小至约53 nm。时域有限差分（FDTD）模拟表明，尖端附近的尺寸梯度增加引起的传播光的最大泄漏的横向功能，精确地确定了由纳米线的固有特性。此外，光谱分裂现象被观察到，并证明基于波长依赖的光在这样的纳米线的传播行为。这些结果有助于合理设计的纳米近场光源，光电，和光生物学探针与改善的分辨率大大优于所谓的亚波长水平上级。
Theoretically, no matter how thin a nanowire is, it can transport light in the form of an evanescent field. However, in practice, the low propagation efficiency induced by complex dissipation makes light transport difficult to realize when the nanowire is distinctly thinner than ∼ λ/2. Accordingly, nanowire photonics research at such a scale is limited. Herein, light propagation was achieved in a very thin spindle nanowire (diameter below 70 nm), in which a nanoscopic spotlight formed. The nanowire output a maximum emission in the transverse dimension as small as ∼53 nm. The finite-difference time-domain (FDTD) simulation implied that the increased dimension gradient near the tip induced a maximum leakage of the propagating light at a transverse feature, precisely determined by the intrinsic feature of the nanowire. Moreover, a spectrum splitter phenomenon was observed and demonstrated based on the wavelength-dependent light propagation behavior in such a nanowire. These results contribute to the rational design of nanoscopic near-field illuminant, optoelectric, and photobiological probes with improved resolution largely superior to the so-called subwavelength level.