基于相干合成的高功率绿光飞秒激光系统  

Coherent Beam Combining-Based High-Power Green Femtosecond Laser System

作　　者：毕根毓 刘博文 余晨鸣[1] 储玉喜 范锦涛 胡明列 Bi Genyu;Liu Bowen;Yu Chenming;Chu Yuxi;Fan Jintao;Hu Minglie(Ultrafast Laser Laboratory&Key Laboratory of Optoelectronic Information Technology(Ministry of Education),School of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Georgia Tech Shenzhen Institute,Tianjin University,Shenzhen 518071,Guangdong,China)

机构地区：[1]天津大学精密仪器与光电子工程学院超快激光研究室&光电信息技术教育部重点实验室,天津300072 [2]天津大学佐治亚理工学院深圳学院,广东深圳518071

出　　处：《中国激光》2025年第2期19-26,共8页Chinese Journal of Lasers

基　　金：国家重点研发计划(2021YFB3602600);国家自然科学基金(62227821);深圳市科技计划(20220618114250001)。

摘　　要：报道了高功率、高光束质量绿光飞秒激光系统。该系统结合了棒状光子晶体光纤放大器和相干合成技术,并使用三硼酸锂(LBO)晶体进行非线性频率变换。单路光纤放大器输出中心波长为1031 nm、重复频率为1 MHz、平均功率为130 W的脉冲序列。通过优化放大器的热管理和改善信号光耦合,在该功率下获得了近衍射极限的光束质量。两路放大器的相干合成效率高达95.2%,且在不同输出功率下保持稳定。在相干合成后,基频光的平均功率达到238 W,经过透射式衍射光栅压缩器后功率为210 W,脉冲宽度为230 fs。通过优化基频光的光斑大小,在2 mm厚的LBO晶体中进行倍频处理,成功输出平均功率为128 W、中心波长为517 nm、脉冲宽度为216 fs的飞秒激光。同时,该高功率绿光飞秒激光系统具有良好的稳定性和可扩展性。Objective This study aims to develop a high-power green femtosecond laser system with a high beam quality by integrating rodtype photonic crystal fiber amplifiers and coherent beam-combining technology.Continuous advancements in laser technology have focused on realizing femtosecond lasers with high average power,high single-pulse energy,and superior beam quality.This study is significant because high-power green femtosecond lasers are crucial for various applications,including micromachining of widebandgap materials,high-quality photonic device processing,extreme ultraviolet generation,pumping optical parametric oscillators,and biomedical imaging.The system design and methodology ensure that the laser maintains high performance and stability,making it a valuable tool for cutting-edge research and technological development.Methods The system employs rod-type photonic crystal fiber amplifiers and coherent beam combining techniques,along with a lithium triborate(LBO)crystal for nonlinear frequency conversion.To ensure near-diffraction-limited beam quality at this power level,both the thermal management of the amplifier and coupling of the seed light were optimized.The thermal management of the amplifier involved the use of a low water-cooling temperature to mitigate the thermal effects that could degrade the beam quality.Two amplifiers were coherently combined with an efficiency of 95.2%,achieving stable output across different power levels.The coherent beam-combining technique utilizes active phase control to maintain the phase coherence between the beams from the two amplifiers.This involves the use of piezoelectric mirrors and feedback systems to correct the phase errors dynamically,ensuring that the power of the combined beam is stable near its maximum value.Moreover,the use of piezoelectric deflection mirrors ensures automatic alignment of the two beams.Fundamental light was compressed using a transmission diffraction grating compressor.By adjusting the grating angle and spacing and finely adjusting the second

关 键 词：超快光学 激光放大器 频率变换 啁啾脉冲放大 相干合成 

分 类 号：O436[机械工程—光学工程]