State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, China.
Sci Rep. 2013;3:1451. doi: 10.1038/srep01451.
Ultra-small all-optical switches are of importance in highly integrated optical communication and computing networks. However, the weak nonlinear light-matter interactions in natural materials present an enormous challenge to realize efficiently switching for the ultra-short interaction lengths. Here, we experimentally demonstrate a submicron bidirectional all-optical plasmonic switch with an asymmetric T-shape single slit. Sharp asymmetric spectra as well as significant field enhancements (about 18 times that in the conventional slit case) occur in the symmetry-breaking structure. Consequently, both of the surface plasmon polaritons propagating in the opposite directions on the metal surface are all-optically controlled inversely at the same time with the on/off switching ratios of >6 dB for the device lateral dimension of <1 μm. Moreover, in such a submicron structure, the coupling of free-space light and the on-chip bidirectional switching are integrated together. This submicron bidirectional all-optical switch may find important applications in the highly integrated plasmonic circuits.
超小型全光开关在高度集成的光通信和计算网络中具有重要意义。然而，天然材料中较弱的非线性光物质相互作用对实现超短相互作用长度的有效开关提出了巨大挑战。在这里，我们实验演示了一种亚微米级的双向全光等离子体开关，具有非对称 T 形单缝。在对称破缺结构中，出现了尖锐的非对称光谱和显著的场增强（约为传统狭缝情况下的 18 倍）。因此，在金属表面上传播的两个相反方向的表面等离子体激元可以同时以超过 6dB 的开/关切换比进行全光控制，而器件的横向尺寸小于 1μm。此外，在这种亚微米结构中，自由空间光的耦合和片上双向开关被集成在一起。这种亚微米级的双向全光开关可能在高度集成的等离子体电路中有着重要的应用。
