共查询到20条相似文献,搜索用时 46 毫秒
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本文介绍一种新型毫米波准光学可调辐射源,它采用由面对称三反射镜准光学谐振腔和绕射光栅组成高频互作用系统,利用中等能量级的相对论带状电子注激励,产生频率可调的宽带毫米波、远红外波段的辐射。这种新方案的机理性实验在电子科技大学首次获得成功,其主要实验参数:电子注的能量为400~500kV,电压脉冲宽度70ns,同步脉冲磁场强度1.2T; 磁场脉冲宽度10ms,带状电子注尺寸10nm×1mm;通过热测实验,我们成功地检测到3mm波段的高频信号,其峰值功率达到数十千瓦量级。 相似文献
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Depolarization loss compensated resonator for electro-optic Q-switched solid-state laser 总被引:2,自引:0,他引:2
A novel laser resonator for compensating depolarization loss that is due to thermally induced birefringence in active rod is reported. As this new structure being applied to an electro-optic Q-switched LDA side-pumped Nd:YAG laser operating at a repetition rate of 1000 Hz, substantial reduction in depolarization loss has been observed, the output pulse energy is improved about 56% from that of a traditional resonator without compensation structure. With incident pump energy of 450 mJ per pulse, linearly polarized output energy of 30 mJ per pulse is achieved, the pulse duration is less than 15 ns, and the peak power of pulse is about 2 MW. The extinction ratio of laser beam is better than 10:1, and the beam divergence is 1.3 mrad with beam diameter of around 2.5 mm. 相似文献
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We report on the results of experimental and theoretical investigation of the shape of an acoustic pulse generated in alkali-halide
crystals by a pulsed electron beam with a maximal electron energy of 0.28 MeV and an energy density of 0.10–0.65 J/cm2. It is found that the shape of the acoustic pulse for the given beam parameters substantially differs from the absorbed energy
density profile. The formation of the fine structure of the acoustic pulse is associated with local release of energy due
to the evolution of multichannel electrical breakdown. 相似文献
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《中国光学快报(英文版)》2017,(2)
The propagation of a filamentary laser beam at an air-glass surface is studied by setting the incident angle satisfying the total reflection condition. The images of the trajectory of the filamentary laser beam inside the sample and the output far-field spatial profiles are measured with varying incident laser pulse energies. Different from the general total reflection, a transmitted laser beam is detected along the propagation direction of the incident laser beam. The energy ratio of the transmitted laser beam depends on the pulse energies of the incident laser beam. The background energy reservoir surrounding the filament core can break the law of total reflection at the air-glass surface, resulting in the regeneration of the transmitted laser beam. 相似文献
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部分端面抽运混合腔板条激光器可以在紧凑的空间内实现大功率高光束质量的激光输出。利用这一技术并结合具有增益高、荧光寿命短等特点的Nd∶YVO4晶体 ,配合新型高重复率的电光Q开关 ,易于实现高频窄脉冲高光束质量的激光输出。在德国EdgeWaveGmbH进行了混合腔电光调Q激光器的合作研究中 ,实现了高重复率近衍射极限的输出 ;在以 5kHz的高重复率运转时 ,获得了单脉冲能量 7 2mJ ,脉宽 5 7ns,平均功率约 36W的脉冲 ;当重复率高达 5 0kHz时 ,输出的激光脉冲的参量是单脉冲能量 1.6mJ,脉宽 9 5ns,平均功率超过 80W。实验所测的光束质量因子M2 小于 2。 相似文献
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A high efficiency, high beam quality diode-pumped Nd:YAG master oscillator power-amplifier (MOPA) laser with six amplifier stages is demonstrated. The oscillator with two-rod birefringence compensation was designed as a thermally determined near hemispherical resonator, which presents a pulse energy of 223 mJ with a beam quality value of M2 = 1.29 at a repetition rate of 108 Hz. The MOPA system delivers a pulse energy of 5.1 J with a pulse width of 230 μs, a M2 factor of 3.6 and an optical-to-optical efficiency of 38.5%. To the best of our knowledge, this is the highest pulse energy for a diode-pumped Nd:YAG rod laser operation with a high beam quality and a pulse width of hundreds of microseconds at a repetition rate of over 100 Hz. 相似文献
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自由电子激光器要求高亮度、低能散度的电子束注入波荡器(Undulator)。本文叙述提供高亮度电子束的高频电子直线加速器中的注入器部分的设计计算。注入器由L波段(1300MHz)的十二分频和三分频两个谐振腔预聚束器和一个基波频率的变相速聚束器组成。粒子运动方程中考虑了空间电荷效应和束流负载效应。电子枪的注入参数:脉冲宽度T=4ns;电流I=5A;电子的初始动能E_0=100keV;电子束分布为高斯型。参数优化设计结果:单束团宽度小于25ps,峰值电流达400A以上,电子的平均归一化能量>4,束团内的能量差小于200keV。 相似文献
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Y. Matsuoka K. Wake T. Nagashima N. Iehisa 《Applied Physics A: Materials Science & Processing》2007,87(1):81-85
Ablation processing of borosilicate glass was carried out using the fourth harmonic of the Q-switch Nd:YAG laser. The dependency
of the ablation depth on irradiation pulse energy density and the dependency of the ablation depth on irradiation spot size
were investigated. The average ablation depth increased with an increase in irradiation pulse energy density. When the irradiation
pulse energy density was the same, the ablation depth of the focused beam with a large spot diameter was deeper than that
of the focused beam with a small spot diameter. To shorten the processing time, an increase in the irradiation pulse energy
density and use of a large spot size focused beam are effective. Using area scanning together with line scanning, a rectangular
through hole (sub-mm size) without cracks or chips was formed in borosilicate glass of 140 μm in thickness.
PACS 52.38.Mf; 42.70.Ce; 42.62.Cf 相似文献
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V. V. Kozlyuk 《Technical Physics》1998,43(5):605-607
The problems of regulating the output energy of the accelerated beam of a backward-wave linear proton accelerator over a wide
range without altering the beam intensity are investigated. The proton energy is regulated by adjusting the duration of the
rf power pulse delivered to the accelerator and by regulating the delay time between the instant of injection and the instant
at which the leading edge of the rf pulse arrives at the output end of the accelerator. The method is tested on the interdigital-type
accelerating section of length 1.25 m of a linear proton accelerator. It is shown experimentally that the electron beam energy
at the accelerator output can be varied approximately threefold without any appreciable sacrifice of the beam intensity by
varying the duration of the rf pulse in the given accelerator section.
Zh. Tekh. Fiz. 68, 135–137 (May 1998) 相似文献
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利用准分子激光等离子体技术,在紫外预电离XeCl准分子激光器上获得了最短1.58 ns的短脉冲激光输出。实验中分析了聚焦到薄膜表面的光束能量密度对所产生的等离子体密度的影响,并对不同等离子体密度及维持时间情况下脉冲压缩效果进行了讨论,给出了激光器谐振腔在稳定腔及非稳腔两种工作方式下的实验结果。激光器在稳定腔工作时,脉宽可压缩至2.87 ns;采用非稳腔结构时,在脉冲能量不变情况下减小聚焦光斑面积,提高入射到薄膜表面的能量密度,得到了最短1.58 ns的短脉冲激光输出。该技术适用于任何其它准分子器件。 相似文献
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In this paper, frequency-doubled Nd:YAG laser's phase conjugation has been investigated experimentally using resonant degenerate four-wave mixing (DFWM). The iodine solution was used as resonant medium. In this way, the energy of the DFWM phase conjugation beam arrived at 43μJ/pulse while the total pump beam's energy reached 8mJ/pulse. The relation between the pulse energy of the DFWM phase conjugation beam and that of the pump beam was investigated. We also measured the optical field distributions of pump beam and DFWM phase conjugation beam, from which it can be noticed that the DFWM phase conjugation can improve the laser beam quality. At the same time, we observed the influence of the pump beam's disturbance on the DFWM signal. 相似文献
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激光脉冲能量对激光诱导Al等离子体辐射特征的影响 总被引:3,自引:0,他引:3
使用Nd:YAG激光器烧蚀金属Al靶获得等离子体,利用光谱时-空分辨技 术,在52 mJ~145 mL/pulse激光脉冲能量范围内,关于激光脉冲能量对激光诱导等离子体 辐射特征的影响进行了研究。使用的气体是Ar气,压强为10 kPa。结果发现,激光脉冲能量 升高,引起特征谱线强度增加,连续谱强度也增加;但能量过高,会击穿周围气体,产生气 体微等离子体。此时,特征谱和连续谱几乎不再增强;最大特征辐射强度在145 mJ、10 kPa 、靶前0.1 mm处、延时180 ns获得;同一条件下获得最强背景连续谱,而信号-背景差是在 145 mJ、10 kPa、靶前1.0 mm处、延时450 ns达到最大值。基于Al等离子体不同激光脉冲能 量下的时间-空间分辨谱,对结果进行了简单的讨论。并分别确定了获得最大特征辐射和信 号-背景差的条件。 相似文献