Yu Renwen, Alaee Rasoul, Boyd Robert W, de Abajo F Javier García
ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Phys Rev Lett. 2020 Jul 17;125(3):037403. doi: 10.1103/PhysRevLett.125.037403.
Transient optical heating provides an efficient way to trigger phase transitions in naturally occurring media through ultrashort laser pulse irradiation. A similar approach could be used to induce topological transitions in the photonic response of suitably engineered artificial structures known as metamaterials. Here, we predict a topological transition in the isofrequency dispersion contours of a layered graphene metamaterial under optical pumping. We show that the contour topology transforms from elliptic to hyperbolic within a subpicosecond timescale by exploiting the extraordinary photothermal properties of graphene. This new phenomenon allows us to theoretically demonstrate applications in engineering the decay rate of proximal optical emitters, ultrafast beam steering, and dynamical far-field subwavelength imaging. Our study opens a disruptive approach toward ultrafast control of light emission, beam steering, and optical image processing.
瞬态光学加热提供了一种通过超短激光脉冲辐照在天然介质中触发相变的有效方法。类似的方法可用于在被称为超材料的适当设计的人工结构的光子响应中诱导拓扑转变。在这里，我们预测了光泵浦下层状石墨烯超材料等频色散轮廓中的拓扑转变。我们表明，通过利用石墨烯非凡的光热特性，轮廓拓扑在亚皮秒时间尺度内从椭圆形转变为双曲线形。这一新现象使我们能够在理论上证明其在工程近端光发射器的衰减率、超快光束转向和动态远场亚波长成像方面的应用。我们的研究为超快控制光发射、光束转向和光学图像处理开辟了一种颠覆性方法。
