Electrically-pumped compact topological bulk lasers driven by band-inverted bound states in the continuum  

作　　者：Song Han Jieyuan Cui Yunda Chua Yongquan Zeng Liangxing Hu Mingjin Dai Fakun Wang Fangyuan Sun Song Zhu Lianhe Li Alexander Giles Davies Edmund Harold Linfield Chuan Seng Tan Yuri kivshar Qi Jie Wang 

机构地区：[1]Centre for Optoelectronics and Biophotonics,School of Electrical and Electronic Engineering&The Photonics Institute,Nanyang Technological University,Singapore,Singapore [2]Electronic Information School,Wuhan University,Wuhan,China [3]school of Electronic and Electrical Engineering,University of Leeds,Leeds,UK [4]Nonlinear Physics Center,Research School of Physics,Australian National University,Canberra,ACT 2601,Australia [5]Division of Physics and Applied Physics,School of Physical and Mathematical Sciences,Nanyang Technological University,Singapore,Singapore

出　　处：《Light(Science & Applications)》2023年第7期1337-1345,共9页光（科学与应用)（英文版）

基　　金：supported by the fundings from Singapore Ministry of Education(MOE),A*STAR Programmatic Funds,and the National Research Foundation Competitive Research Program that correspond the grants MOET2EP50120-0009,A18A7b0058,and NRF-CRP23-2019-0007,respectively;L.L A.G.D.,and E.H.L.acknowledge founding support from the EPSRC(UK)Hyper Terahertz programme(EP/P021859/1);the Royal Society,and the Wolfson Foundation.Y.K.acknowledges a founding support from the Australian Research Council(grant DP200101168).

摘　　要：One of the most exciting breakthroughs in physics is the concept of topology that was recently introduced to photonics,achieving robust functionalities,as manifested in the recently demonstrated topological lasers.However,so far almost all attention was focused on lasing from topological edge states.Bulk bands that reflect the topological bulk-edge correspondence have been largely missed.Here,we demonstrate an electrically pumped topological bulk quantum cascade laser(QCL)operating in the terahertz(THz)frequency range.In addition to the band-inversion induced in-plane reflection due to topological nontrivial cavity surrounded by a trivial domain,we further illustrate the band edges of such topological bulk lasers are recognized as the bound states in the continuum(BiCs)due to their nonradiative characteristics and robust topological polarization charges in the momentum space.Therefore,the lasing modes show both in-plane and out-of-plane tight confinements in a compact laser cavity(lateral size~3λ_(laser)).Experimentally,we realize a miniaturized THz QCL that shows single-mode lasing with a side-mode suppression ratio(SMSR)around 20 dB.We also observe a cylindrical vector beam for the far-field emission,which is evidence for topological bulk BIC lasers.Our demonstration on miniaturization of single-mode beam-engineered THz lasers is promising for many applications including imaging,sensing,and communications.

关 键 词：PUMPED polarization LASING 

分 类 号：TN2[电子电信—物理电子学]