An actively ultrafast tunable giant slow-light effect in ultrathin nonlinear metasurfaces
An actively ultrafast tunable giant slow-light effect in ultrathin nonlinear metasurfaces
复制标题
超薄非线性超表面中的主动超快可调巨型慢光效应
DOI：
10.1038/lsa.2015.75
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发表时间：
2015-06-01
影响因子：
19.4
通讯作者：
Gong, Qihuang
中科院分区：
文献类型：
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作者：
Lu, Cuicui;Hu, Xiaoyong;Gong, Qihuang
基于超材料诱导透明（MIT）的慢光效应在集成光子器件中具有重要的实际应用价值。然而，迄今为止，由于金属的固有损耗，在超材料中仅获得了非常弱的慢光效应。此外，在超材料中还没有实现对慢光的主动控制。在这里，我们报告了一个巨大的慢光效应的实现上的超颖表面，由金纳米棱镜二聚体的周期性阵列，厚度为40纳米之间的多层石墨烯微片/氧化锌纳米颗粒层和单层石墨烯/多晶氧化铟锡层夹。与MIT相关联的等离子体激元模式的强场限制确保了透明窗口周围的群速度的巨大降低。群指数大于4× 103，比以往报道的群指数提高了一个数量级。当泵浦光强度仅为1.5 kW cm-2时，在透明窗口的中心周围实现了120 nm的大的可调谐波长范围。响应时间最快可达42.3ps。这些结果表明，基于超表面的各种功能集成光子器件的实现，如全光缓冲器和全光开关的潜力。
A slow-light effect based on metamaterial-induced transparency (MIT) possesses great practical applications for integrated photonic devices. However, to date, only very weak slow-light effects have been obtained in metamaterials because of the intrinsic loss of metal. Moreover, no active control of slow-light has been achieved in metamaterials. Here, we report the realization of a giant slow-light effect on an ultrathin metasurface that consists of periodic arrays of gold nanoprism dimers with a thickness of 40 nm sandwiched between a multilayer-graphene micro-sheet/zinc oxide nanoparticle layer and a monolayer graphene/polycrystalline indium tin oxide layer. The strong field confinement of the plasmonic modes associated with the MIT ensures a tremendous reduction in the group velocity around the transparency window. A group index of more than 4× 10 3 is achieved, which is one order of magnitude greater than that of previous reports. A large tunable wavelength range of 120 nm is achieved around the center of the transparency window when the pump light intensity is only 1.5 kW cm− 2. The response time is as fast as 42.3 ps. These results demonstrate the potential for the realization of various functional integrated photonic devices based on metasurfaces, such as all-optical buffers and all-optical switches.