Efficient second harmonic generation by harnessing bound states in the continuum in semi-nonlinear etchless lithium niobate waveguides  

作　　者：Xueshi Li Jiantao Ma Shunfa Liu Peinian Huang Bo Chen Dunzhao Wei Jin Liu 

机构地区：[1]State Key Laboratory of Optoelectronic Materials and Technologies,School of Physics,Sun Yat-Sen University,510275 Guangzhou,China

出　　处：《Light(Science & Applications)》2022年第11期2774-2781,共8页光（科学与应用)（英文版）

基　　金：National Key R&D Program of China(2021YFA1400803);Guangdong Natural Science Funds for Distinguished Young Scholars(2022B1515020067);National Natural Science Foundation of China(11904424,11874437,62035017);Key-Area R&D Program of Guangdong Province(2018B030329001);The Fundamental Research Funds for the Central Universities,Sun Yat-sen University(221gqb32).

摘　　要：Integrated photonics provides unprecedented opportunities to pursue advanced nonlinear light sources with lowpower consumptions and small footprints in a scalable manner,such as microcombs,chip-scale optical parametric oscillators and integrated quantum light sources.Among a variety of nonlinear optical processes,high-efficiency second harmonic generation(SHG)on-chip is particularly appealing and yet challenging.In this work,we present efficient SHG in highly engineerable semi-nonlinear waveguides consisting of electron-beam resist waveguides and thin-film silicon nitride(SiN)/lithium niobate(LN).By carefully designing octave-separating bound states in the continuum(BICs)for the nonlinear interacting waves in such a hybrid structure,we have simultaneously optimized the losses for both fundamental frequency(FF)and second harmonic(SH)waves and achieved modal phasing matching and maximized the nonlinear modal overlap between the FF and SH waves,which results in an experimental conversion efficiency up to 4.05%W^(-1)cm^(-2).Our work provides a versatile and fabrication-friendly platform to explore on-chip nonlinear optical processes with high effciency in the context of nanophotonics and quantum optics.

关 键 词：NONLINEAR HARMONIC LITHIUM 

分 类 号：TN25[电子电信—物理电子学]