神龙二号加速器是一台以M H z 猝发率猝发工作的三脉冲直线感应电子加速器.该加速器输出的三脉冲电子束,相邻两脉冲间最小时间间隔300 n s ,而且可调,每个脉冲电子束的电子能量1 8 -20 M e V 、束流强度大于等于2 k A .当电子束与轫致...神龙二号加速器是一台以M H z 猝发率猝发工作的三脉冲直线感应电子加速器.该加速器输出的三脉冲电子束,相邻两脉冲间最小时间间隔300 n s ,而且可调,每个脉冲电子束的电子能量1 8 -20 M e V 、束流强度大于等于2 k A .当电子束与轫致辐射转换靶相互作用时,可产生三个强X 光脉冲,X 光斑点尺寸小于等于2 m m （ F W H M ）,距靶1 m 处照射量大于等于7 . 7 4 × 1 0^- 2C /k g （ 0 0 R ）.该加速器涉及的主要关键技术包括三脉冲功率源设计、三脉冲强流高品质电子束源的产生、加速场建造、束流传输线设计、轫致辐射转换靶设计、测量与诊断技术等.展开更多
We report a Yb-doped all-fiber laser system generating burst-mode pulses with high energy and high peak power at a GHz intra-burst repetition rate.To acquire the uniform burst envelope,a double-pre-compensation struct...We report a Yb-doped all-fiber laser system generating burst-mode pulses with high energy and high peak power at a GHz intra-burst repetition rate.To acquire the uniform burst envelope,a double-pre-compensation structure with an arbitrary waveform laser diode driver and an acoustic optical modulator is utilized for the first time.The synchronous pumping is utilized for the system to reduce the burst repetition rate to 100 Hz and suppress the amplified spontaneous emission effect.By adjusting the gain of every stage,uniform envelopes with different output energies can be easily obtained.The intra-burst repetition rate can be tuned from 0.5 to 10 GHz actively modulated by an electro-optic modulator.Optimized by timing control of eight channels of analog signal and amplified by seven stages of Yb-doped fiber amplifier,the pulse energy achieves 13.3 mJ at 0.5 ns intra-burst pulse duration,and the maximum peak power reaches approximately3.6 MW at 48 ps intra-burst pulse duration.To the best of our knowledge,for reported burst-mode all-fiber lasers,this is a record for output energy and peak power with nanosecond-level burst duration,and the widest tuning range of the intra-burst repetition rate.In particular,this flexibly tunable burst-mode laser system can be directly applied to generate high-power frequency-tunable microwaves.展开更多
Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.Th...Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.The origin of deterioration in processing accuracy could be interpreted in terms of the discontinuous movement of plasma in the vicinity of the focus.To reveal the effectiveness of the temporal energy modulation for smootli machining,such plasma motion was simulated by the fiidtc-d ifference time-domain method.F urt her more,photoinduced birefringence was observed using a high-speed polarization camera.展开更多
Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly p...Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.展开更多
基于脉冲压缩技术进行脉冲簇高脉冲重复频率的时序设计,采用不同中心频率的参考信号进行全去斜处理的方法,然后通过低通滤波器进行滤除,将混叠脉冲进行有效分离。处理方法具有灵活性和多样性,可以提高系统的脉冲重复频率,可以实现12%以...基于脉冲压缩技术进行脉冲簇高脉冲重复频率的时序设计,采用不同中心频率的参考信号进行全去斜处理的方法,然后通过低通滤波器进行滤除,将混叠脉冲进行有效分离。处理方法具有灵活性和多样性,可以提高系统的脉冲重复频率,可以实现12%以上的占空比。高脉冲重复频率的脉冲簇设计,可以获得高采样数,对于星载的应用具有重要意义。通过仿真进行验证,可以达到5~13 k Hz的高脉冲重复频率。展开更多
文摘神龙二号加速器是一台以M H z 猝发率猝发工作的三脉冲直线感应电子加速器.该加速器输出的三脉冲电子束,相邻两脉冲间最小时间间隔300 n s ,而且可调,每个脉冲电子束的电子能量1 8 -20 M e V 、束流强度大于等于2 k A .当电子束与轫致辐射转换靶相互作用时,可产生三个强X 光脉冲,X 光斑点尺寸小于等于2 m m （ F W H M ）,距靶1 m 处照射量大于等于7 . 7 4 × 1 0^- 2C /k g （ 0 0 R ）.该加速器涉及的主要关键技术包括三脉冲功率源设计、三脉冲强流高品质电子束源的产生、加速场建造、束流传输线设计、轫致辐射转换靶设计、测量与诊断技术等.
基金supported by the National Natural Science Foundation of China(No.62205374)the Research Funds of the State Key Laboratory of Pulsed Power Laser Technology,China(Nos.SKL2021KF07 and SKL2020ZR06)
文摘We report a Yb-doped all-fiber laser system generating burst-mode pulses with high energy and high peak power at a GHz intra-burst repetition rate.To acquire the uniform burst envelope,a double-pre-compensation structure with an arbitrary waveform laser diode driver and an acoustic optical modulator is utilized for the first time.The synchronous pumping is utilized for the system to reduce the burst repetition rate to 100 Hz and suppress the amplified spontaneous emission effect.By adjusting the gain of every stage,uniform envelopes with different output energies can be easily obtained.The intra-burst repetition rate can be tuned from 0.5 to 10 GHz actively modulated by an electro-optic modulator.Optimized by timing control of eight channels of analog signal and amplified by seven stages of Yb-doped fiber amplifier,the pulse energy achieves 13.3 mJ at 0.5 ns intra-burst pulse duration,and the maximum peak power reaches approximately3.6 MW at 48 ps intra-burst pulse duration.To the best of our knowledge,for reported burst-mode all-fiber lasers,this is a record for output energy and peak power with nanosecond-level burst duration,and the widest tuning range of the intra-burst repetition rate.In particular,this flexibly tunable burst-mode laser system can be directly applied to generate high-power frequency-tunable microwaves.
文摘Suppression of stress and crack generation during picosecond laser processing in transparent brittle materials such as glass was successfully demonstrated by a picosecond laser pulse with temporal energy modulation.The origin of deterioration in processing accuracy could be interpreted in terms of the discontinuous movement of plasma in the vicinity of the focus.To reveal the effectiveness of the temporal energy modulation for smootli machining,such plasma motion was simulated by the fiidtc-d ifference time-domain method.F urt her more,photoinduced birefringence was observed using a high-speed polarization camera.
文摘Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.
文摘基于脉冲压缩技术进行脉冲簇高脉冲重复频率的时序设计,采用不同中心频率的参考信号进行全去斜处理的方法,然后通过低通滤波器进行滤除,将混叠脉冲进行有效分离。处理方法具有灵活性和多样性,可以提高系统的脉冲重复频率,可以实现12%以上的占空比。高脉冲重复频率的脉冲簇设计,可以获得高采样数,对于星载的应用具有重要意义。通过仿真进行验证,可以达到5~13 k Hz的高脉冲重复频率。
