Topological nanospaser

Nanophotonics

article

Rupesh Ghimire¹  Jhih-Sheng Wu¹  Vadym Apalkov¹  Mark I. Stockman¹ 

[1] Center for Nano-Optics (CeNO) and Department of Physics and Astronomy, Georgia State University

关键词: near-field optics;    spaser;    optical pumping;    plasmonics;    symmetry protected topological states;    topological materials;    valleytronics;   

DOI  :  10.1515/nanoph-2019-0496

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

We propose a nanospaser made of an achiral plasmonic–metal nanodisk and a two-dimensional chiral gain medium – a monolayer nanoflake of a transition-metal dichalcogenide (TMDC). When one valley of the TMDC is selectively pumped (e.g. by a circular-polarized radiation), the spaser (surface plasmon amplification by stimulated emission of radiation) generates a mode carrying a topological chiral charge that matches that of the gain valley. There is another, chirally mismatched, time-reversed mode with exactly the same frequency but the opposite topological charge; it is actively suppressed by the gain saturation and never generates, leading to a strong topological protection for the generating matched mode. This topological spaser is promising for use in nano-optics and nanospectroscopy in the near field especially in applications to biomolecules that are typically chiral. Another potential application is a chiral nanolabel for biomedical applications emitting in the far field an intense circularly polarized coherent radiation.

【 授权许可】

CC BY