论文标题
来自二维极性金属的意外近红外至可见的非线性光学特性
Unexpected Near-Infrared to Visible Non-linear Optical Properties from Two-Dimensional Polar Metals
论文作者
论文摘要
描述了近红外至可见的第二次谐波产生，从空气稳定的二维极性镀金和indim颗金属中描述。 2D金属的光子性能 - 包括金属报告的最大的二阶易感性（接近10nm $^2 $/V） - 由原子级结构和两到三个原子的结晶膜的结合确定。键字符在几个原子层上从共价转化为金属，将平面外金属金属键距离降低了约百分之十（0.2 $ \ unicode {x212b} $），从而导致对称性破坏和轴向静电二极管介导了大型非线性反应。晶体金属原子的两个不同方向，对应于横向位移<2 $ \ unicode {x212b} $，在单独的微米尺度露台上持续存在，以生成不同的谐波极化。这种强大的原子级结构 - 质体相互作用表明金属光子性能可以通过原子精度来控制。
Near-infrared-to-visible second harmonic generation from air-stable two-dimensional polar gallium and indium metals is described. The photonic properties of 2D metals - including the largest second-order susceptibilities reported for metals (approaching 10nm$^2$/V) - are determined by the atomic-level structure and bonding of two-to-three-atom-thick crystalline films. The bond character evolved from covalent to metallic over a few atomic layers, changing the out-of-plane metal-metal bond distances by approximately ten percent (0.2 $\unicode{x212B}$), resulting in symmetry breaking and an axial electrostatic dipole that mediated the large nonlinear response. Two different orientations of the crystalline metal atoms, corresponding to lateral displacements < 2 $\unicode{x212B}$, persisted in separate micron-scale terraces to generate distinct harmonic polarizations. This strong atomic-level structure-property interplay suggests metal photonic properties can be controlled with atomic precision.
