基于准参量非线性晶体的非厄米超快激光放大  

Non-Hermitian ultrafast laser amplification with quasi-parametric nonlinear crystals

作　　者：钟亥哲[1] 钟一凡 王文昊 王静 马金贵 钱列加 ZHONG Haizhe;ZHONG Yifan;WANG Wenhao;WANG Jing;MA Jingui;QIAN Liejia(International Collaborative Laboratory of 2D Materials for Optoelectronic Science&Technology,Institute of Microscale Optoelectronics,Shenzhen University,Shenzhen 518060,China;Key Laboratory for Laser Plasmas(Ministry of Education),School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]深圳大学微纳光电子学研究院,二维材料光电科技国际合作联合实验室,广东深圳518060 [2]上海交通大学物理与天文学院,激光等离子体教育部重点实验室,上海200240

出　　处：《厦门大学学报（自然科学版）》2023年第2期174-186,共13页Journal of Xiamen University：Natural Science

基　　金：广东省自然科学基金(2023A1515030014,2020A1515010541);深圳市科技计划项目(JCYJ20220531103411026)。

摘　　要：激光振荡器锁模是激光物理中的重要发现和超快科学中的核心技术,其本质是以耗散调控增益,进而改变激光振荡行为.这种以耗散调控增益的概念离不开谐振腔的反馈耦合,长期以来多局限于激光振荡器.对此,本文首先提出了准参量非线性的概念,不同于传统的二阶非线性光参量过程,准参量非线性基于耗散闲频光的准参量晶体,通过非线性耦合实现了以闲频光耗散对信号光放大的调控,对应着量子理论中的具有宇称-时间对称性的非厄米体系.准参量的放大行为由信号光增益、闲频光耗散以及非线性耦合三者之间的相互作用决定,起始阶段的信号光放大继续保持传统光参量放大的特性,而在最终的饱和放大阶段则呈现出类似能级型放大的非参量特性,从而同时具备光参量放大和激光能级型放大的综合优势.其次给出了准参量非线性的反直觉的超快应用:实现无需谐振腔的放大器锁模.最后,对这种基于准参量晶体的非厄米超快激光放大在激光物理创新中的更多未来应用前景进行总结展望.As an important discovery in laser physics and a core technology in ultrafast science,the laser mode-locking allows the control of laser oscillations by gain through loss.However,this concept becomes invalid for a laser amplifier that lacks the cavity feedback.Recently,we propose the concept of quasi-parametric nonlinearity.In contrast to the traditional second-order parametric interaction,the quasi-parametric interaction relies on a nonlinear crystal with idler dissipation.The control of signal amplification by idle dissipation is realized through nonlinear coupling and corresponds to a type of non-Hermitian quantum systems.Owing to the interaction of gain,loss and coupling,the quasi-parametric amplification shows completely different amplification behaviors.In the initial phase,it maintains characteristics of optical parametric amplification and presents non-parametric characteristics similar to those of laser gain amplification in the saturation amplification stage,thus securing a combined advantage of both optical parametric amplification and laser gain amplification.We will also show the counterintuitive application of quasi-parametric nonlinearity to achieve ultrafast mode-locking in laser amplifiers without cavity.Finally,we will anticipate potential applications of ultrafast non-Hermitian nonlinear optics.

关 键 词：非线性光学 非厄米光子学 啁啾脉冲放大 准参量放大 

分 类 号：TN248[电子电信—物理电子学]