光学莫尔晶格中超短脉冲的脉宽调控  

Modulation of Ultrashort Pulse Width in Optical MoiréLattices

作　　者：赵学谦 刘志楠 刘辉[1,2] Zhao Xueqian;Liu Zhinan;Liu Hui(National Laboratory of Solid State Microstructures,School of Physics,Nanjing University,Nanjing 210093,Jiangsu,China;Collaborative Innovation Center of Advanced Microstructures,School of Physics,Nanjing University,Nanjing 210093,Jiangsu,China)

机构地区：[1]南京大学物理学院固体微结构物理国家重点实验室,江苏南京210093 [2]南京大学物理学院人工微结构科学与技术协同创新中心,江苏南京210093

出　　处：《光学学报》2023年第20期298-305,共8页Acta Optica Sinica

基　　金：国家自然科学基金(92163216,92150302,62288101)。

摘　　要：具有莫尔角的光学莫尔晶格使能带平坦化,为激光超短脉冲的脉宽调控提供了新的思路。通过组合两种不同周期的光子晶格,构建3种人工合成莫尔角逐渐增大的光学莫尔晶格,实现了莫尔晶格能带的平坦化。通过理论分析莫尔晶格的能带色散,发现人工合成莫尔角较大的莫尔晶格具有丰富的群速度色散,这导致了脉宽的剧烈变化。实验上,使用自相关仪测量了超短脉冲经莫尔晶格后的脉宽。在理论和实验上证明了莫尔晶格对超短脉冲脉宽的精准调控。提出的莫尔晶格对激光脉冲压缩器件的研究具有重要意义。Objective Ultrashort pulses,with a pulse duration of tens of picoseconds(10–12 ps)or less,are timing tools with the highest precision available currently.Their narrow pulse width and high peak power characteristics have considerably advanced the development of nonlinear optics.However,ultrashort pulse lasers unavoidably suffer from the dispersion introduced by various optical elements during their operation,resulting in pulse deformation and power attenuation,which adversely affect the performance of ultrashort pulses.Therefore,extensive research has been conducted on pulse width regulation.The current solution is primarily based on the utilization of dispersion-compensation devices,which suffer from low integration characteristics and nonactive regulation.Recently,the optical Moiréstructure has become a widely discussed topic due to its high potential in the modulation of light field by changing Moiréangles.However,most published works introduce physical twisted angles,and optical Moiréstructures combined with the concept of synthetic dimensions have rarely been reported.Therefore,we propose an optical Moirélattice with artificially synthesized Moiréangles to achieve ultrashort pulse width modulation.Methods A method of constructing optical Moirélattices with artificially synthesized Moiréangles(nonphysical twisted angles)is proposed herein.Moirélattices comprise two simple photonic lattices with different periods,and the ratio of the arctangents of their periods represents the Moiréangle of the optical Moirélattice.Three optical Moirélattices with gradually increasing Moiréangles are theoretically designed,and the band structure of the optical Moirélattices is determined by the transfer matrix method;we observe that the increase in Moiréangles leads to the flattening of the band structure.The band dispersion is further analyzed,following which the group velocity and pulse width changes introduced by an ultrashort pulse through the Moirélattices are computed.The theoretical calculations demonstr

关 键 词：光学莫尔晶格 超短脉冲 群速度色散 自相关仪 脉宽调控 

分 类 号：O436[机械工程—光学工程]