中国物理B ›› 2024, Vol. 33 ›› Issue (1): 14206-14206.doi: 10.1088/1674-1056/ad011b

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

Yuan-Zhai Xu(许元斋)1,2, Zhen-Ling Li(李珍玲)1,2, Ao-Nan Zhang(张奥楠)1,2, Ke Liu(刘可)1,†, Jing-Jing Zhang(张晶晶)1,2, Xiao-Jun Wang(王小军)1, Qin-Jun Peng(彭钦军)1, and Zu-Yan Xu(许祖彦)1   

  1. 1 Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2023-09-19 修回日期:2023-09-30 接受日期:2023-10-07 出版日期:2023-12-13 发布日期:2023-12-25
  • 通讯作者: Ke Liu E-mail:liuke0209@mails.ucas.ac.cn
  • 基金资助:
    Project supported by Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2020029).

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

Yuan-Zhai Xu(许元斋)1,2, Zhen-Ling Li(李珍玲)1,2, Ao-Nan Zhang(张奥楠)1,2, Ke Liu(刘可)1,†, Jing-Jing Zhang(张晶晶)1,2, Xiao-Jun Wang(王小军)1, Qin-Jun Peng(彭钦军)1, and Zu-Yan Xu(许祖彦)1   

  1. 1 Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2023-09-19 Revised:2023-09-30 Accepted:2023-10-07 Online:2023-12-13 Published:2023-12-25
  • Contact: Ke Liu E-mail:liuke0209@mails.ucas.ac.cn
  • Supported by:
    Project supported by Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2020029).

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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 M2 ≈ 1.4.

关键词: pulse-burst, beam combining, nonlinear optics

Abstract: 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 M2 ≈ 1.4.

Key words: pulse-burst, beam combining, nonlinear optics

中图分类号:  (Nonlinear optics)

  • 42.65.-k
42.65.Re (Ultrafast processes; optical pulse generation and pulse compression)