Jana Kamalesh, Okocha Emmanuel, Møller Søren H, Mi Yonghao, Sederberg Shawn, Corkum Paul B
Department of Physics, University of Ottawa, Advanced Research Complex (ARC) 25 Templeton Street Ottawa, Ottawa, ON, K1N 6N5, Canada.
Nanophotonics. 2021 Nov 11;11(4):787-795. doi: 10.1515/nanoph-2021-0501. eCollection 2022 Jan 4.
Structuring light-matter interaction at a deeply subwavelength scale is fundamental to optical metamaterials and metasurfaces. Conventionally, the operation of a metasurface is determined by the collective electric polarization response of its lithographically defined structures. The inseparability of electric polarization and current density provides the opportunity to construct metasurfaces from current elements instead of nanostructures. Here, we realize metasurfaces using structured light rather than structured materials. Using coherent control, we transfer structure from light to transient currents in a semiconductor, which act as a source for terahertz radiation. A spatial light modulator is used to control the spatial structure of the currents and the resulting terahertz radiation with a resolution of , or approximately at a frequency of 1 THz. The independence of the currents from any predefined structures and the maturity of spatial light modulator technology enable this metasurface to be reconfigured with unprecedented flexibility.
在深亚波长尺度上构建光与物质的相互作用是光学超材料和超表面的基础。传统上，超表面的运行由其光刻定义结构的集体电极化响应决定。电极化和电流密度的不可分割性为用电流元件而非纳米结构构建超表面提供了机会。在此，我们使用结构化光而非结构化材料来实现超表面。通过相干控制，我们将结构从光转移到半导体中的瞬态电流，这些电流充当太赫兹辐射源。使用空间光调制器以 的分辨率（在1太赫兹频率下约为 ）来控制电流的空间结构以及由此产生的太赫兹辐射。电流独立于任何预定义结构以及空间光调制器技术的成熟，使得这种超表面能够以前所未有的灵活性进行重新配置。
