Special Colloquium
Department of Physics, NCU
Chiral Plasmonic Nano Laser
Speaker
Dr. Jhih-Sheng Wu (吳致盛博士)
T4 & Center for Integrated Nanotechnology,
RCAS Academia Sinica
Date 2020.03.06(Fri)
Time 12:00PM
Place S4-625
| Abstract: |
Research of the light-matter interactions below the wavelength scale, nano-optics, is gaining more momentums recently. Manipulating chirality of light is a grand challenge of nano-optics. Plasmons in condensed matter systems such as metal nanoparticles and two-dimensional materials are promising to overcome the grand challenge. Among the developments of nano-plasmonics, a breakthrough, surface plasmon amplification by stimulated emission of radiation (spaser), was theoretically introduced in 2003 by Mark I. Stockman. Spaser is a non-Hermitian system with gain and loss exhibiting nonlinearity and nanoscale coherent strong light. Such confined field can be coupled with the topological properties of a periodical structure. We proposed two kinds of chiral spasers due to their topological natures: (1) Spontaneous symmetry breaking creates topological charges of a metal array in the reciprocal space, which lead to a chiral spaser. We showed that because of competitions for common gain, a honeycomb array of metal nanoparticles with an achiral gain stably generates chiral lasing. (2) 2D materials serve as topological gain materials to make a chiral spaser. We showed that a spaser of a metal nano-disk has a chirality locked to the valleys of 2D materials.