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Nonlinear Anisotropic Dielectric Metasurfaces for Ultrafast Nanophotonics
ACS Photonics ( IF 6.5 ) Pub Date : 2017-09-01 00:00:00 , DOI: 10.1021/acsphotonics.7b00544
Giuseppe Della Valle 1 , Ben Hopkins 2 , Lucia Ganzer 1 , Tatjana Stoll 1 , Mohsen Rahmani 2 , Stefano Longhi 1 , Yuri S. Kivshar 2 , Costantino De Angelis 3 , Dragomir N. Neshev 2 , Giulio Cerullo 1
Affiliation  

We report on the broadband transient optical response of anisotropic, amorphous silicon nanobricks that exhibit Mie-type resonances. A quantitative model is developed to identify and disentangle the three physical processes that govern the ultrafast changes of the nanobrick optical properties, namely, two-photon absorption, free-carrier relaxation, and lattice heating. We reveal a set of operating windows where ultrafast all-optical modulation of transmission is achieved with full return to zero in 20 ps. This is made possible because of the distinct dispersive features exhibited by the competing nonlinear processes in transmission and despite the slow (nanosecond) internal lattice dynamics. The observed ultrafast switching behavior can be independently engineered for both orthogonal polarizations using the large anisotropy of nanobricks, thus allowing ultrafast anisotropy control. Our results categorically ascertain the potential of all-dielectric resonant nanophotonics as a platform for ultrafast optical devices and reveal the possibility for ultrafast polarization-multiplexed displays and polarization rotators.

中文翻译:

超快纳米光子学的非线性各向异性介电超表面。

我们报告了呈现Mie型共振的各向异性非晶硅纳米砖的宽带瞬态光学响应。建立定量模型以识别和解开控制纳米砖光学特性超快变化的三个物理过程,即两个光子吸收,自由载流子弛豫和晶格加热。我们揭示了一组工作窗口,可实现超快的全光传输调制,并在20 ps内完全归零。尽管有缓慢的(纳秒级)内部晶格动力学,但由于竞争中的非线性过程在传输中表现出独特的色散特性,因此使之成为可能。观察到的超快开关行为可以使用纳米砖的大各向异性针对两个正交极化进行独立设计,因此可以实现超快各向异性控制。我们的研究结果明确地确定了全介电共振纳米光子作为超快光学器件平台的潜力,并揭示了超快偏振多路复用显示器和偏振旋转器的可能性。
更新日期:2017-09-04
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