熔融石英中实现高效率的百毫焦受激布里渊散射  

Generation of high-efficiency hundred-millijoule stimulated Brillouin scattering in fused silica

作　　者：陈彬[1,2] 白振旭 赵桂娟 王雨雷 吕志伟 Chen Bin;Bai Zhenxu;Zhao Guijuan;Wang Yulei;Lu Zhiwei(Center for Advanced Laser Technology,Hebei University of Technology,Tianjin 300401,China;Hebei Key Laboratory of Advanced Laser Technology and Equipment,Tianjin 300401,China;Jinan Lashan Aviation Technology Co.,Ltd,Jinan 250117,China)

机构地区：[1]河北工业大学先进激光技术研究中心,天津300401 [2]河北省先进激光技术与装备重点实验室,天津300401 [3]济南腊山航空科技有限公司,山东济南250117

出　　处：《红外与激光工程》2023年第8期294-297,共4页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(61927815,62075056);天津市自然科学基金项目(20JCZDJC00430,22JCYBJC01100)。

摘　　要：固体布里渊增益介质是目前实现高稳定、高重复频率受激布里渊散射(SBS)的重要光学元件,能够产生高光束质量的相位共轭光。然而,不同于被广泛研究的液体布里渊增益介质,目前针对固体布里渊增益介质如何产生高效率高能量的SBS尚无成熟的研究。近日,笔者团队以块状熔融石英作为布里渊增益介质,在高强度纳秒激光脉冲泵浦下,围绕熔融石英中的SBS能量转换效率和损伤阈值与泵浦光纵模的关系开展了研究,实现了最高单脉冲能量183.1 mJ、反射率为81.0%、斜效率高达85.8%的相位共轭光输出。该研究结果对于实现高功率全固态的SBS相位共轭镜,进而提升脉冲激光器的输出功率水平、获得高稳定高效率的SBS运转具有重要的指导意义。Objective Stimulated Brillouin scattering(SBS)is a powerful tool for serving as a phase conjugation mirror(PCM)due to its inherent properties of high gain,small frequency shift,and phase conjugation.Solid-state gain media offer the advantages of high stability and high repetition rate SBS,compared to liquid and gas gain media.However,solid gain media face the challenge of recovery once breakdown occurs.Currently,there is limited research on achieving high-efficiency and high-energy SBS generation in solid media,which restricts the application of solid gain media in high-energy SBS.In this study,we experimentally investigate an SBS generator based on bulk fused silica to provide guidance for the development and application of all solid-state SBS systems with high efficiency.Methods The experimental setup is illustrated(Fig.1).A passively Q-switched nanosecond laser,based on a ring cavity,is used as the pump source,delivering a pulse width of 10 ns.A Fabry-Perot etalon is inserted into the cavity to control the number of longitudinal modes.Lenses L1 and L2 are utilized to adjust the beam diameter from 3.2 mm to 5.6 mm,while the focal length of L3 is 250 mm.Fused silica,with a length of 200 mm,serves as the Brillouin gain medium.The output characteristics of SBS generation,including threshold,slope efficiency,damage threshold,and beam profile,are studied by varying the pump mode and pump intensity.Results and Discussions Compared to a single longitudinal-mode(SLM)pump,the SBS threshold for a multilongitudinal-mode(MLM)pump is 14%higher,and the damage threshold is only 34 mJ(Fig.2(a)).A phaseconjugate reflectivity of up to 81.0%,with a slope efficiency of 85.8%,is achieved when the pump single pulse energy is 183.1 mJ.The results indicate that MLM pulse spikes are the key factor causing optical breakdown in the SBS process,while SLM pumping can effectively prevent the optical breakdown in solid media.The narrowest Stokes pulse width of 5.5 ns is obtained at an energy reflectivity of 15%;While the waveform maintains g

关 键 词：受激布里渊散射 熔融石英 高效率 损伤阈值 纵模 

分 类 号：O437.2[机械工程—光学工程]