共查询到20条相似文献,搜索用时 93 毫秒
1.
频率分辨光学开关法是目前测量超短激光脉冲的主流方法之一.本文比较了三大类二次谐波频率分辨光学开关系统的特点和适用范围,提出将标准二次谐波频率分辨光学开关法改装成一种快速扫描频率分辨光学开关法(frequency-resolved optical gating, FROG)装置.利用信号发生器输出的正弦信号同步地驱动音圈电机和扫描振镜,其中音圈电机带动直角反射镜往复运动可实现快速的延时扫描,与此同时扫描振镜快速转动进而按照延时顺序将自相关信号光谱反射至面阵相机感光面上的不同位置.该正弦信号还用于触发面阵相机持续曝光,即可拍摄到一幅完整的FROG迹线图,曝光时间可小于1 s.该方案在需要记录较大矩阵FROG迹线图的情形颇具优势,例如可实现色散大的啁啾脉冲和结构复杂的超短脉冲的实时测量.通过测量从自锁模钛宝石激光器输出的飞秒脉冲以及被200 mm厚的BK7玻璃块展宽后的啁啾脉冲的结构,证实了该装置的实用性. 相似文献
2.
建立了一台频率分辨偏振光学开关(PG FROG)法飞秒脉冲测量装置,利用该装置对“极光Ⅱ号”飞秒激光放大系统进行了测量.在利用偏振光学开关法测得的时域和频域信号基础上,结合对信号光强度分布的计算机迭代处理,得到了有关飞秒激光电场、光谱及其相位的信息;并且对系统工作在不同状态时的激光脉冲进行了测量和比较分析,给出了有关该系统较详细的电场、光谱、相位以及啁啾状况.结果显示,当系统工作在零啁啾附近时,该系统输出的激光脉冲的电场、光谱和相位分布较规则,相位起伏较小;当系统偏离零啁啾状态时,虽然电场和光谱变化不很明显,但相位分布变化剧烈.
关键词:
频率分辨偏振光学开关(PG FROG)法
飞秒激光
自相关 相似文献
3.
《中国光学与应用光学文摘》2004,(1)
TN247 2004010183 飞秒激光脉冲的谐波频率分辨光学开关法测量研究=Measurement of femtosecond laser pulses using SHG frequency-resolved optical gating technique[刊,中]/王兆华(中科院物理所光物理开放实验室.北京(100080)),魏志义…∥物理学报.—2003,52(2).—362-366 建立了一台谐波频率分辨光学开关法(FROG)飞秒 相似文献
4.
5.
飞秒激光在激光核聚变、卫星精密测距、激光微加工等领域具有重要的应用前景,同时也是产生太赫兹波的主要泵浦源。介绍了国内外飞秒激光脉冲宽度和脉冲波形的测试方法,比较了自相关法、频率分辨光学快门法、光谱相位相干直接电场重构法的优缺点。自相关法具有脉宽测量范围广、结构简单等特点,但不具备脉冲波形测试能力。光谱相位相干直接电场重构法对待测激光光束质量要求较高, 不适合大量程范围激光脉宽快速测量。为满足10 fs~5 ps大量程范围超短激光脉冲宽度和脉冲波形的测试需求,采用自相关法及二次谐波频率分辨光学开关法研制飞秒激光脉冲宽度和脉冲波形测试仪,时间分辨率优于2 fs。 相似文献
6.
超宽光谱的飞秒脉冲测量一直是超快激光领域的重要研究方向之一.常规的飞秒脉冲自相关方法是通过测量自相关倍频信号来获得,而倍频信号具有波长选择性,不同中心波长的飞秒脉冲测量需要更换不同的倍频晶体,十分不方便.因此,提出了一种改进型的瞬态光栅频率分辨光学开关(TG-FROG)方法用于测量飞秒脉冲.该方法结合四波混频和频率分辨光学开关方法,其基本过程是将待测脉冲分为三束,其中两束脉冲经过精密的延时控制并聚焦在光学介质上达到时空重合,利用三阶非线性效应产生稳定的瞬态光栅作为开关光;另一束脉冲作为探测光与产生的瞬态光栅进行相互作用产生一个信号光,使用光谱仪对该信号光的光谱与延迟时间进行测量,并通过反演迭代算法处理而获取待测飞秒脉冲的光谱与电场信息.该方法只需要待测光的功率密度达到三阶非线性效应就可以实现测量,因此可以应用于任意中心波长的飞秒脉冲测量.利用该方法对中心波长分别为800 nm, 400 nm的飞秒脉冲,以及超连续亚10 fs的周期量级超宽光谱飞秒脉冲进行了测量,并与常规的干涉自相关仪器测量结果进行了比较,所得测量结果基本一致.实验结果表明,建立的基于TG-FROG方法对不同中心波长,不同脉冲宽度的飞秒脉冲测量是十分有效的. 相似文献
7.
8.
9.
10.
自衍射效应在飞秒激光领域有非常重要的应用,如提高飞秒脉冲的时域对比度、作为自参考光谱干涉脉冲测量法的参考光、作为频率分辨光学开关法的信号光等.然而,具有较宽光谱带宽的飞秒激光在自衍射效应过程中产生的信号光存在明显的角色散,这给自衍射效应的应用带来不利影响.本文研究发现通过在自衍射效应的一个光路中加入等腰直角棱镜,当到棱镜的入射角为23fi时可以明显地减小飞秒激光脉冲自衍射信号的角色散.这就为以后将自衍射效应更好的应用到飞秒激光脉冲的研究提供了有用的参考. 相似文献
11.
Emission characteristics of a single heterostructure GaAs diode laser are reported using a simple driver circuit. It provides
a single picosecond time duration optical pulse, a pulse train or a broad optical pulse depending on the amplitude and time
duration of the electrical pump pulse. Results show that relaxation oscillation frequency depends on the amplitude of pumping
current pulse as well as on some inherent property of diode laser, which seems to be the level of impurity in lasing medium.
Variation of relaxation oscillation frequency with amplitude of current pulse shows only the qualitative agreement with the
reported theoretical predictions. 相似文献
12.
By simultaneously using both an acoustic-optic (AO) modulator and a V3+:YAG saturable absorber in the cavity, for the first time to our knowledge, a diode-pumped doubly Q-switched Nd:GdVO 4 laser has been realized. The dependence of pulse width, pulse energy and peak power on the incident pump power at determinate pulse repetition rate are measured. Under the absorbed pump power of 8.59 W, the pulse temporal profile of the AO-switching with the pulse duration of 14.5 ns, the double Q-switching with pulse duration of 7.6 ns at 10 kHz, and the passive Q-switching with pulse duration of 22.3 ns are obtained. The pulse duration is obviously compressed in contrast to the purely actively AO Q-switched laser or the purely passively Q-switched laser with V3+:YAG. 相似文献
13.
A femtosecond fiber laser based on thulium-doped double-clad silica fiber with an internal dispersion compensation is presented that generates pulses at a center wavelength of 1976 nm with an energy of 4.3 nJ and a duration of 1.2 ps. The dechirped pulse duration is 294 fs. The pulse energy is more than 2 orders of magnitude above the pulse energy demonstrated previously. Mode locking is achieved using additive pulse mode locking, and dispersion compensation is facilitated by a grating stretcher arrangement. 相似文献
14.
T. Ejdrup H. T. Lemke K. Haldrup T. N. Nielsen D. A. Arms D. A. Walko A. Miceli E. C. Landahl E. M. Dufresne M. M. Nielsen 《Journal of synchrotron radiation》2009,16(3):387-390
The recent developments in X‐ray detectors have opened new possibilities in the area of time‐resolved pump/probe X‐ray experiments; this article presents the novel use of a PILATUS detector to achieve X‐ray pulse duration limited time‐resolution at the Advanced Photon Source (APS), USA. The capability of the gated PILATUS detector to selectively detect the signal from a given X‐ray pulse in 24 bunch mode at the APS storage ring is demonstrated. A test experiment performed on polycrystalline organic thin films of α‐perylene illustrates the possibility of reaching an X‐ray pulse duration limited time‐resolution of 60 ps using the gated PILATUS detector. This is the first demonstration of X‐ray pulse duration limited data recorded using an area detector without the use of a mechanical chopper array at the beamline. 相似文献
15.
Multiple amplification stages with different phase-matching angles were designed to yield stable and ultrabroadband amplification
in optical parametric chirped pulse amplification by optimally controlling the idler laser pulses. Numerical results showed
that the overall temporal duration of the amplified seed laser pulse and subsequently the spectral bandwidth can be amplified
by using multiple amplification stages in comparison with those of the initial seed pulse laser, which is suitable to generate
a high-energy pulse with ultrashort pulse duration in a simple manner. 相似文献
16.
We demonstrate sub-100-fs resolution of a cross-correlation method for measuring the duration of soft-X-ray pulses. The method uses the ultra-fast increase in a singly charged ion population induced by optical-field ionization as a soft-X-ray -absorption switch. We measured the pulse duration of the 51st harmonic of a Ti:sapphire laser pulse using Kr gas as a soft-X-ray absorption medium and found it to be 60 fs assuming that the harmonic envelope is equal to a squared secant hyperbolic. This confirmed that our method achieves a shorter temporal resolution than the 100-fs pulse duration of the ionizing laser pulse. The temporal resolution obtained in this way is expected to be from one-third to one-half the duration of the ionizing laser pulse, according to our calculation of the time-evolving population of the Kr+ ions. The experimental demonstration and calculation show that methods based on optical-field-induced ionization are promising for femtosecond temporal characterization of an ultra-short pulse in the soft-X-ray region. PACS 42.50.Hz; 42.65.Ky; 32.80.Rm; 06.60.Jn 相似文献
17.
18.
A. N. Didenko A. E. Shikanov V. I. Rashchikov V. I. Ryzhkov V. L. Shatokhin 《Technical Physics》2014,59(6):904-910
The generation of neutron pulses with a duration of 1–100 ns using small vacuum accelerating tubes is considered. Two physical models of acceleration of short deuteron bunches in pulse neutron generators are described. The dependences of an instantaneous neutron flux in accelerating tubes on the parameters of pulse neutron generators are obtained using computer simulation. The results of experimental investigation of short-pulse neutron generators based on the accelerating tube with a vacuum-arc deuteron source, connected in the circuit with a discharge peaker, and an accelerating tube with a laser deuteron source, connected according to the Arkad’ev-Marx circuit, are given. In the experiments, the neutron yield per pulse reached 107 for a pulse duration of 10–100 ns. The resultant experimental data are in satisfactory agreement with the results of computer simulation. 相似文献
19.
20.
V. A. Astapenko 《Journal of Experimental and Theoretical Physics》2020,130(1):56-61
The dynamics of photoexcitation of the hydrogen atom in the discrete and continuous spectra under the action of laser pulses in the attosecond range of time and pulse durations has been analyzed using perturbation theory. It is shown that over time interval shorter than or on the order of pulse duration, the time dependence of the photoexcitation probability is generally oscillating by nature. It has been established that for certain values of parameters, the envelope of this dependence has a peak, the position of which is determined by the pulse duration and carrier frequency. 相似文献