高剂量率单次快脉冲辐射参量测量

记述了“强光一号”高剂量率脉冲辐射装置在状态调试过程中对其出射波形和辐射剂量进行监测的基本情况，实际监测的结果与设计方监测的结果进行了比对，双方的剂量监测值基本一致，偏差在20％以内；双方的波形形状十分相似，但测量得到的波形半宽度却相差10～20ns，最后对双方束流监测产生的差异进行了定性分析。     

A Possibility for Studying Gravitational Properties of the Neutrino

We consider the effect that the gravitational field of a neutrino pulse radiated in the collapse of presupernova nuclei has on the observable optical radiation spectra of atoms at the supernova surface. We show that at the modern level of development of experimental methods, neutrino monitoring supplemented by optical monitoring of supernova candidates provides a unique possibility to check whether the Einstein equivalence principle is satisfied for neutrinos of each of the three types (electron, muon, and tau-lepton) and their antiparticles, to estimate the change of the gravitational potential at the surface of the star at the instant of the neutrino radiation pulse, and to obtain upper limits on the mass values of these neutrinos in a new way.     

The structure of multi-electrode-pair pulse laser and discharge pulse time selection

Applying multi-electrode-pair pulse TEA CO₂ laser to one optical resonance cavity will have several advantages over traditional method, including higher gain, shorter pulse discharge time interval, and in particular, continuous adjustable time interval of multi-pulse laser output can be achieved without high vacuum condition. To improve laser's working stabilization, we proposed new approaches to optimize laser structure design and discharge pulse time interval selection.     

Relative intensity noise of mode-locked fiber grating external cavity semiconductor lasers

The noise of hybrid soliton pulse source (HSPS) with linearly chirped Gaussian apodized fiber Bragg grating is analyzed by couple-mode equations including spontaneous emission noise when the HSPS is mode-locked. Relative intensity noise is calculated using numerical solutions of these equations. It is shown that transform limited pulses are generated over a wide tuning range around the fundamental mode-locking frequency with low spontaneous noise. However, a high noise level affects the operation of device, and therefore transform-limited pulses are not obtainable over a wide tuning range. It is also shown that noise is extremely sensitive to the RF and DC currents, linewidth enhancement factor, gain saturation parameter and spontaneous coupling factor.     

超短脉冲激光微束对细胞作用的研究

本文详细地介绍了我们自己设计和安装的一个Nd:YAG超短脉冲激光微束系统,该系统分成二个部分:激光源和显微镜。由电光调Q非稳腔Nd:YAG激光倍频后得到355nm紫外光进入显微镜并由物镜聚焦。同时,这超短脉冲激光微束照射在细胞上并且在细胞上产生一个可以自恢复的小孔。在文中我们还讨论了超短脉冲激光微束与细胞之间作用效应及机理。     

Time resolved laser-induced plasma dynamics

The structure and evolution of the laser-induced vapor plume and shockwave were measured from femtosecond time resolved shadowgraph images. By changing the wavelength of the probe beam (400 and 800 nm), differences in the opacity of the vapor plume were measured as a function of delay time from the ablation laser pulse. The evolution of the temperature and electron number density during and after the ablation laser pulse were determined and compared for ablation in argon and helium background gases. A laser supported detonation wave (LSD) observed for ablation in argon, blocks the incoming laser energy and generates a high-pressure region above the vapor plume.     

不同倾角的脉管制冷机内自然对流影响的研究

本文通过对脉管内自然对流的数值模拟，讨论了当脉管冷端处在不同方向时，脉管内的自然对流对脉管制冷机性能的影响．数值模拟结果表明，当冷端在下时获得的制冷温度最低；当热端在下并与重力方向成３０°时制冷温度最高．结论与实验测量结果定性一致．所做的理论分析对实现脉管制冷机的良好运行有指导意义。     

长脉冲相对论速调管中束流脉冲缩短的研究

介绍L波段长脉冲相对论速调管放大器研究中，长脉冲强流相对论电子束(IREB)经过输入腔和中间腔间隙后的脉冲缩短问题.分析了造成束流脉冲缩短的主要机理之一是高频系统的角向非均匀模式与电子束相互作用而使得束流扩散形成的，并经过实验参数的调节，减轻了长脉冲IREB的脉冲缩短问题，得到了较强的基波调制电流.从长脉冲加速器引出500 kV，3.5 kA，1.3 μs的电子束，经过输入腔和两个群聚腔的调制后，得到了2.0 kA的基波调制电流，束流脉冲宽度由0.3 μs增加到1 μs，束流脉冲缩短问题得到明显减轻. 关键词： 相对论速调管放大器 脉冲缩短 高功率微波 长脉冲强流相对论电子束     

Femtosecond dynamics of secondary radiation formation from quantum well excitons

The time-resolved secondary emission of resonantly created excitons in GaAs quantum wells is studied using femtosecond up-conversion spectroscopy. The behaviour of the rise and decay of the secondary emission and reflectivity in quantum wells is strongly dependent upon the disorder at the interfaces, the exciton density and the temperature. In the case of low densities and temperatures the emission is independent of the exciton density and rises quadratically in time, in excellent agreement with recent theory for Rayleigh scattering from two-dimensional excitons subjected to disorder. These rise times are compared directly with times measured by time-integrated four-wave mixing (FWM). The comparison of the dynamics displayed in time-resolved secondary radiation and time-integrated FWM provide a clear understanding of the coherence properties of QW excitons in the first few picoseconds after excitation. High-contrast oscillations that are due to quantum beats between the heavy- and light-hole 1s-states are seen. The visibility decay at very low densities is long ps and is related to the action of potential fluctuations on the scattering of heavy-hole and light-hole excitons.     

Constructive and Destructive Two-Pulse Excitation Investigated with a White-Light Michelson Interferometer

Linear propagation of two pulses through methanol solution of aluminum phthalocyanine chloride is investigated using a modified white-light Michelson interferometer. The observed coherence time of the white light is 6 fs, and the separation between the two-excitation pulses is set to about 10 fs. The excitation is dependent on the phase-relation between the two pulses. We have observed an enhancement of the excitation when the two pulses are in-phase and strong suppression of the excitation when the two pulses are out of phase by π.