Using harmonic beam combining to generate pulse-burst in nonlinear optical laser  

作　　者：许元斋 李珍玲 张奥楠 刘可 张晶晶 王小军 彭钦军 许祖彦 Yuan-Zhai Xu;Zhen-Ling Li;Ao-Nan Zhang;Ke Liu;Jing-Jing Zhang;Xiao-Jun Wang;Qin-Jun Peng;Zu-Yan Xu(Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Physics B》2024年第1期422-427,共6页中国物理B（英文版）

基　　金：Project supported by Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.2020029)。

摘　　要：The ultrashort lasers working in pulse-burst mode reveal great machining performance in recent years. The number of pulses in bursts effects greatly on the removal rate and roughness. To generate a more equal amplitude of pulses in burst with linear polarization output and time gap adjustable, we propose a new method by the harmonic beam combining(HBC).The beam combining is commonly used in adding pulses into the output beam while maintaining the pulse waveform and beam quality. In the HBC, dichroic mirrors are used to combine laser pulses of fundamental wave(FW) into harmonic wave(HW), and nonlinear crystals are used to convert the FW into HW. Therefore, HBC can add arbitrarily more HW pulses to generate pulse-burst in linear polarization with simple structure. The amplitude of each pulse in bursts can be adjusted the same to increase the stability of the burst, the time gap of each pulse can be adjusted precisely by proper time delay. Because HBC adds pulses sequentially, the peak power density of the burst is the same as each pulse, pulses can be combined without concern of back-conversion which often occurs in high peak power density. In the demonstration, the extendibility of HBC was verified by combining two beams with a third beam. The combined efficiency rates were larger than 99%, and the beam quality of each beam was maintained at M^(2)≈1.4.

关 键 词：pulse-burst beam combining nonlinear optics 

分 类 号：TN248[电子电信—物理电子学] O437[机械工程—光学工程]