共查询到20条相似文献,搜索用时 377 毫秒
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阐述了短脉冲激光装置中脉冲前沿畸变效应的产生机理和可能的畸变源.利用Fourier光学方法,建立了一个基于单程压缩构型的研究脉冲前沿畸变效应的理论模型,分析不同种脉冲前沿畸变效应对于压缩器输出脉冲的近场时空特性的影响.基于此,对一个在建的大口径(300 mm)短脉冲装置中的各种畸变源(包括可编程声光光谱色散滤波器、透镜色差以及劈板等元件)进行了数值计算.研究表明:近场输出脉冲宽度显著加宽,输出脉冲前沿形状不同于输入时的畸变形状,只有中心部分区域的脉冲前沿形状与输入类似,该区域的大小由系统带宽决定.
关键词:
脉冲前沿畸变
角色散
单程压缩
透镜 相似文献
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We review the state of the art of ultrashort-light-pulse measurement using frequency-resolved-optical-gating (FROG). Recent developments have extended the state of the art considerably. FROG devices for measuring the intensity and phase of ultrashort laser pulses have become so simple that almost no alignment is required. In addition, such devices not only operate single shot, but they also yield the two most important spatio-temporal distortions, spatial chirp and pulse-front tilt. With other FROG variations, it is now possible to measure more general ultrashort light pulses (i.e., pulses much more complex than common laser pulses), with time-bandwidth products as large as several thousand and as weak as a few hundred photons, and despite other difficulties such as random absolute phase and poor spatial coherence. 相似文献
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We present a method of adjusting the pulse duration and eliminating the pulse-front tilt of an ultrashort pulse in real time by use of a specially configured single-shot autocorrelator. Pulse-front tilt, or a temporal delay across the pulse front, is a common ultrashort-pulse phenomenon when dispersive elements are being used. We show the design of an autocorrelator that can be used to eliminate the pulse-front tilt and simultaneously adjust the pulse duration in real time by adjustment of the pulse compressor of a chirped-pulse amplified laser system. 相似文献
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Jiying Huang Wang He Shuhong Gong 《International Journal of Infrared and Millimeter Waves》2007,28(10):889-899
When a pulse wave propagates through fog, the effects of distortion, being severer at millimeter wave band, is caused by fog
because of its dispersive property. The transfer function of a pulse signal is obtained by the theory of radio wave propagation;
the complex envelope is deduced by the solution of Fourier integral. The broadening and compressing effects of a pulse wave
are discussed. The variations of distortion effects with pulse-width, propagation distance and visibility of fog are found.
As an example, the simulating and calculating results of distortion effects for Gaussian pulse at millimeter wave band are
given. 相似文献
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In this work we present a matrix analysis of the sensitivity of otherwise dispersionless 4f and 2f-2f optical systems to misalignments resulting in spatio-temporal distortions of ultrashort laser pulses. Special attention is given to the possible creation of a pulse-front tilt (PFT). The exact analytical expression for the second-harmonic interferometric autocorrelation signal of an inverted-field autocorrelator is calculated. It confirms the effective broadening of the ultrashort pulses in the presence of an arbitrary PFT. 相似文献
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A new method for measuring the pulse-front distortion of arbitrary shapes in high-power ultrashort laser systems 下载免费PDF全文
We present a new method that can be used to calculate pulse-front distortion by measuring the spectral interference of two point-diffraction fields in their overlapped district.We demonstrate,for the first time,the measurement of the pulse-front distortion of the pulse from a complex multi-pass amplification system,which exists in almost all high-power laser systems,and obtain the irregular pulse-front distribution.The method presented does not need any reference light or assumption about the pulse-front distribution,and has an accuracy of several femtoseconds. 相似文献
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The propagation of ultrashort few-cycle laser pulses through a quantum nonlinear medium with resonant properties is studied using the method of slowly varying amplitudes with allowance for dispersion effects. A self-consistent system of nonlinear wave equation for the evolution of laser field and the nonstationary Schrödinger equation that determines the material polarization response is numerically solved. Specific features of the propagation of laser pulse caused by a relatively large spectral width and the nonadiabatic character of the laser pulse are established. The rise of the slowly dumping polarization at the eigenfrequency of the medium and the consequent stretching of the laser pulse are observed. The role of the resonant absorption of the laser energy in the medium is analyzed. The nonlinear spectral broadening is demonstrated for the laser pulse propagating through the medium. 相似文献
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A new method for measuring the pulse-front distortion of arbitrary shapes in high-power ultrashort laser systems 下载免费PDF全文
We present a new method that can be used to calculate pulse-front distortion by measuring the spectral interference of two point-diffraction fields in their overlapped district. We demonstrate, for the first time, the measurement of the pulse-front distortion of the pulse from a complex multi-pass amplification system, which exists in almost all high-power laser systems, and obtain the irregular pulse-front distribution. The method presented does not need any reference light or assumption about the pulse-front distribution, and has an accuracy of several femtoseconds. 相似文献
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Andreev N.E. Chegotov M.V. Downer M.C. Gaul E.W. Matlis N.H. Pogosova A.A. Rundquist A.R. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(4):1090-1097
By simultaneously and self-consistently solving Maxwell's equations, the Ammosov-Delone-Krainov (ADK) field ionization equation, and the relativistic cold plasma equations, we have investigated the propagation of intense, ultrashort laser pulses through spatially inhomogeneous longitudinal gas gradients. Along with highly accurate calculations of the spatial and temporal beam profiles of the pulse at the end of various gradients, we have also determined simple scaling rules for the location of the vacuum-gas interface in order to minimize the pulse distortion at the focus. We show the benefits of using either preionized or low-Z gases, and we discuss the implications of this work for plasma-channel laser wakefield acceleration 相似文献
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We present the results of numerical modeling of passage of ultrashort laser pulses through an inhomogeneous layered medium
with moving scatterers, based on solution of the nonsteady-state radiation transport equation by the Monte Carlo method. We
consider the effects of Doppler broadening of the backscattered radiation spectrum in biological tissues. We have analyzed
the dynamics of propagation of a short laser pulse within a multilayer model of human skin. We have studied the possibilities
for tomography of different layers of biological tissue based on analysis of the spectrum of the scattered radiation pulse. 相似文献
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We investigate the possibility of optical pulse compression of high energy ultrashort laser pulses in an argon-filled planar waveguide, based on two level coupled mode theory and the full 3D nonlinear Schr?dinger equation. We derive general expressions for controlling the spatial beam profile and the extent of the spectral broadening. The analysis and simulations suggest that the proposed method should be appropriate for optical pulse compression of ultrashort laser pulses with energies as high as 600 mJ. 相似文献
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A. D. Debus M. Bussmann M. Siebold A. Jochmann U. Schramm T. E. Cowan R. Sauerbrey 《Applied physics. B, Lasers and optics》2010,100(1):61-76
We present a novel high-yield Thomson scattering geometry that takes advantage of compact electron bunches, as available in
advanced, low-emittance linear accelerators or laser wakefield accelerators. In order to avoid the restrictions on the X-ray
photon yield imposed by the Rayleigh limit, we use ultrashort, pulse-front tilted laser pulses in a side-scattering geometry.
Such a traveling-wave setup allows an overlap of electron and laser beams, even after propagating over distances much longer
than the Rayleigh length. Experimental designs are discussed and optimized for different scattering angles. Specifically,
to minimize group delay dispersion at large scattering angles >10°, we propose the use of varied-line spacing (VLS) gratings
for spatio-temporal laser pulse shaping. Compared to head-on (180°) Thomson scattering, interaction lengths are in the centimeter
to meter range and photon numbers for ultrashort X-ray pulses can increase by several orders of magnitudes. 相似文献
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YY Wang X Peng M Alharbi CF Dutin TD Bradley F Gérôme M Mielke T Booth F Benabid 《Optics letters》2012,37(15):3111-3113
We report on the recent design and fabrication of kagome-type hollow-core photonic crystal fibers for the purpose of high-power ultrashort pulse transportation. The fabricated seven-cell three-ring hypocycloid-shaped large core fiber exhibits an up-to-date lowest attenuation (among all kagome fibers) of 40 dB/km over a broadband transmission centered at 1500?nm. We show that the large core size, low attenuation, broadband transmission, single-mode guidance, and low dispersion make it an ideal host for high-power laser beam transportation. By filling the fiber with helium gas, a 74?μJ, 850?fs, and 40?kHz repetition rate ultrashort pulse at 1550?nm has been faithfully delivered at the fiber output with little propagation pulse distortion. Compression of a 105?μJ laser pulse from 850?fs down to 300?fs has been achieved by operating the fiber in ambient air. 相似文献
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We present an experiment in which an ultrashort pulse train propagates resonantly through anoptically dense vapor of atomic rubidium. The sequence obtained from a Fabry-Perot interferometer comprises nearly 10 regularly time-delayed and mode-locked pulses. We show that a sequence with phase shift phi = 0[2pi] between two successive pulses propagates with important temporal distortion, whereas a sequence with phi = pi[2pi] experiences few propagation effects, thus leading for the first time to our knowledge to the possibility of phase control of dispersion effects for an ultrashort pulse train. 相似文献
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The filamentational instability of spatially broadband femtosecond optical pulses in air is investigated by means of a kinetic wave equation for spatially incoherent photons. An explicit expression for the spatial amplification rate is derived and analyzed. It is found that the spatial spectral broadening of the pulse can lead to stabilization of the filamentation instability. Thus optical smoothing techniques could optimize current applications of ultrashort laser pulses, such as atmospheric remote sensing. 相似文献