Title: Electrically-pumped topological photonic crystals lasers

Speaker: Wang Qijie

Time: 2025-10-14 14:00

Venue: Room W105,Physics Building

Abstract: In electrically-pumped semiconductor lasers, microfabricated structures like photonic crystals have been employed to reduce device footprints. Recently, topological concepts have been integrated into the design of photonic crystal lasers, enabling unprecedented robustness to perturbations and unique laser performance. In this talk I will present how band topology, which is invariant under small deformations, generates robust topological lasing states in semiconductor laser flatforms. In addition, I will introduce how photonic crystals lasers are designed using other promising topological concepts, such as Dirac vortex (or Majorana zero) cavities and topologically nontrivial flatband bound states in the continuum (BICs), for achieving robustness of lasing frequencies, structural beam engineering, and miniaturization while maintaining good laser performance.

Bio: Prof WANG Qiie is a President Chair Professor in Optoelectronics at the School of Electrical and Electronic Engineering (EEE) and the School of Physical and Mathematical Sciences (SPMS) NTU. He is an OPTICA Fellow. He is a co-recipient of the Institution of Engineers Singapore, Prestigious Engineering Achievement Team Award of Singapore Twice in 2005 and 2017, respectively, the prestigious Singapore Young Scientist Award 2014, Nanyang Research Award 2015 (Young Investigator), ARC Sciences Nanotechnology Medal and Prize 2021, and NTU College of Engineering Research Excellence Award 2022.