共查询到20条相似文献,搜索用时 62 毫秒
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Ginzburg N. S. Yurovsky L. A. Vilkov M. N. Zotova I. V. Sergeev A. S. Samsonov S. V. Yakovlev I. V. 《Radiophysics and Quantum Electronics》2019,62(7-8):472-480
Radiophysics and Quantum Electronics - We demonstrate the possible implementation of the chirped pulse amplification (CPA) method, which is widely used in optics, for the microwave frequency band.... 相似文献
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The equivalent temporal complex parameter for Sech type pulses is introducted. The pulse transformation property and optimum compression condition are derived when the pulse passes through grating pair. 相似文献
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A. A. Eltchaninov S. D. Korovin I. V. Pegel V. V. Rostov M. I. Yalandin 《Radiophysics and Quantum Electronics》2003,46(10):782-789
We study theoretically and experimentally the possibility of generation of ultrashort powerful microwave pulses. The regime of spatial accumulation of electromagnetic energy is considered in the case where the pulse propagates oppositely to the electron flow in a long slow-wave structure. We show that during transformation of the kinetic energy of electrons to the energy of an electromagnetic pulse, the pulse power is not limited by the electron-beam power. Using compact high-current accelerators, we obtain gigawatt pulses in the 3-cm and 8-mm wavelength ranges with power conversion factor exceeding unity. 相似文献
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We consider a boundary-value problem for nonlinear total internal reflection of laser pulses from a semi-infinite thermally nonlinear medium. Numerical modeling of the pulse forming upon reflection under the conditions of interaction of counter-propagating waves in a scheme with a retrodirective mirror has been carried out the approximation of noninterfering pulses, the possibility of controlling the shape and compression of the pulse in the nanosecond range of durations has been shown. The results obtained are in qualitative agreement with the known experimental data. 相似文献
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Physics of the Solid State - The effect of magnetization formation for paramagnetic ions with spin S = 1 in a solid under a zero magnetic field by pulsed manipulations with electron spins has been... 相似文献
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V. G. Andreev V. A. Vdovin A. A. Karabutov 《Radiophysics and Quantum Electronics》2003,46(8-9):707-712
We propose a method for detection of the envelope of a microwave nanosecond pulse, which is based on the effect of generation of sound pulses resulting from absorption of electromagnetic waves. We show that to reproduce exactly the envelope shape of a short microwave pulse, it is necessary that the wave be absorbed in a layer of thickness much less than the product of the sound speed and the pulse duration. In searching for conditions ensuring this, we study the process of thermoacoustic generation in thin metal films deposited on quartz substrates. Measurements performed at a wavelength of 8 mm show that the absorption coefficient is maximum if the aluminum-film thickness is 22–25 Å. The maximum absorption coefficient amounts to 49% if the wave is incident from the quartz-substrate side. It is important that in this case, the wave reflection coefficient does not exceed 44%, whereas an aluminum plate reflects almost completely (99.8%) the incident-wave power. The phenomena observed in thin metal films are explained theoretically in terms of the anomalous skin effect. An experimental setup for a study of generation of ultrasonic signals by powerful microwave pulses is described. 相似文献
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在高重复频率的光窄脉冲源中,为了获得更窄的脉冲,需要增加泵浦功率|但泵浦功率的提高会使光放大器的增益趋于饱和,放大的自发辐射噪音增强,脉冲光信噪比下降.为此,提出了利用啁啾管理和光纤光参量放大相结合的脉冲压窄方案.将强度调制后的泵浦光通过相位调制引入线性负啁啾,由于经参量过程后在新的闲频光上啁啾会加倍,从而进一步增大了信号的谱宽,并通过色散补偿介质实现了光脉冲压缩.实验给出了10 GHz速率下的结果,通过泵浦光的相位调制在0.5 W平均泵浦光功率条件下得到了脉宽19 ps的光脉冲,结果与理论分析基本吻合. 相似文献
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A. L. Vikharev A. M. Gorbachev O. A. Ivanov V. A. Isaev S. V. Kuzikov B. Z. Movshevich J. L. Hirshfield S. H. Gold 《Radiophysics and Quantum Electronics》2008,51(7):539-555
We present the results of studies of the active compressor of 3-cm wavelength microwave pulses, which uses a high-Q storage
Bragg resonator excited at the H01 mode and new types of plasma switches. Phase variation during a compressed pulse and phase correlation of the input and compressed
microwave pulses are studied both experimentally and theoretically. Using a single-channel compressor excited at the megawatt
power level by the magnicon radiation with frequency 11.4 GHz, a power amplification factor equal to 9 was reached for an
output-pulse duration of 40–50 ns and a peak power of up to 25 MW.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 7, pp. 597–616, July 2008. 相似文献
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皮秒脉冲在色散缓变光纤中的孤子效应压缩 总被引:11,自引:4,他引:11
本文给出了描述皮秒脉冲在色散缓变单模光纤中孤子效应压缩过程的数学模型。通过数值求解,首次对该孤子效应压缩进行了全面的计算和分析。结果表明,与常规光纤相比,采用色散缓变程度合适的光纤压缩皮秒脉冲,不仅能显著地提高压缩后脉冲的峰值功率和脉冲压缩比,而且能有效地消除压缩后脉冲的次峰和脉座。对于确定的脉冲输入,发现,当光纤的色散缓变程度取某一最佳值时,能获得最佳的压缩效果。进一步研究表明,色散的这一最佳变 相似文献
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1.3μmDFB半导体激光超短脉冲的产生及其压缩 总被引:1,自引:1,他引:1
本文首次报道1.3μm单模超短脉冲产生及压缩实验。通过梳状波电脉冲直接调制DCPBH-DFB半导体激光器,获得22ps单模光滑脉冲;然后利用G-T干涉仪压缩得到近变换极限超短脉冲。脉宽为9.3ps,峰值功率超过200mW,重复频率1GHz,时间带宽乘积为0.39,脉冲压缩比为2.4。最后对实验结果进行了讨论。 相似文献
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We demonstrate theoretically that Li atoms can be transferred to states of a lower principal quantum number by exposing them to a frequency chirped microwave pulse. The population transfer of Li atoms from the n = 75 state to n = 70 with more than 90% efficiency is achieved by means of the sequential single-photon △n = -1 transitions. The calculation fully utilizes all of the available orbital angular momentum l states for a given n, and the interference pattern and population evolution dynamics of individual l states are analyzed in detail. Using the time-dependent multilevel approach, we describe the process reasonably well as a sequence of adiabatic rapid passages. 相似文献
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We have demonstrated a combination of frequency comb spin-echo protocol in a conventional microwave pulsed electron spin resonance spectrometer with gradient pulses of the external magnetic field applied for on-demand retrieval of signal microwave pulses at the required moments of time. A natural high-finesse periodic structure was used as a carrier of stored information. The structure is made out of hyperfine lines of electron spin resonance of tetracyanoethylene anion radicals in toluene at room temperature. Herein, we have also observed that using the pulses of gradient magnetic field can increase the memory capacity. The experimental results demonstrated promising opportunities for controlling electron nuclear spin coherence, which could be useful for implementation of broadband microwave or optical-microwave noise free quantum memory protocols. 相似文献
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Russian Physics Journal - An overview was done of the efficient devices designed to measure the energy of powerful electromagnetic radiation pulses of the relativistic microwave sources –... 相似文献
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In the experiment with an electron energy of ≈500 keV, the long-pulse (~300T, where T is the oscillation period) the generation regime of a relativistic Cherenkov microwave oscillator without a guiding magnetic field at a carrier frequency of 3.8 GHz has been obtained. A high-power microwave radiation pulse length of ~75 ns, a peak generation power of 210 ± 30 MW, and a power conversion efficiency of 9 ± 2% were attained. 相似文献