Dual bound states in the continuum enhanced second harmonic generation with transition metal dichalcogenides monolayer  

作　　者：Peilong Hong Lei Xu Mohsen Rahmani 

机构地区：[1]School of Optoelectronic Science and Engineering,University of Electronic Science and Technology of China(UESTC),Chengdu 611731,China [2]Advanced Optics&Photonics Laboratory,Department of Engineering,School of Science&Technology,Nottingham Trent University,Nottingham NG118NS,UK.

出　　处：《Opto-Electronic Advances》2022年第7期16-23,共8页光电进展（英文）

基　　金：financial supports from the National Natural Science Foundation of China(Grant No.11604150);Fundamental Research Funds for the Central Universities of China(Grant No.ZYGX2020J010);M.Rahmani.acknowledges support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)。

摘　　要：The emergence of two dimensional(2D)materials has opened new possibilities for exhibiting second harmonic genera-tion(SHG)at the nanoscale,due to their remarkable optical response related to stable excitons at room temperature.However,the ultimate atomic-scale interaction length with light makes the SHG of Transition Metal Dichalcogenides(TM-Ds)monolayers naturally weak.Here,we propose coupling a monolayer of TMDs with a photonic grating slab that works with doubly resonant bound states in the continuum(BIC).The BIC slabs are designed to exhibit a pair of BICs,reson-ant with both the fundamental wave(FW)and the second harmonic wave(SHW).Firstly,the spatial mode matching can be fulfilled by tilting FW's incident angle.We theoretically demonstrate that this strategy leads to more than four orders of magnitude enhancement of SHG efficiency than a sole monolayer of TMDs,under a pump light intensity of 0.1 GW/cm^(2).Moreover,we demonstrate that patterning the TMDs monolayer can further enhance the spatial overlap coefficient,which leads to an extra three orders of magnitude enhancement of SHG efficiency.These results demonstrate remarkable pos-sibilities for enhancing SHG with nonlinear 2D materials,opening many opportunities for chip-based light sources,nano-lasers,imaging,and biochemical sensing.

关 键 词：second harmonic generation transition metal dichalcogenides bound state in the continuum photonic grating slab 

分 类 号：O469[理学—凝聚态物理] TB34[理学—电子物理学]