Numerical analysis of near electromagnetic fields of a parabolic cylinder and a paraboloid of revolution

Translated from Chislennye Metody Resheniya Obratnykh Zadach Matematicheskoi Fiziki, pp. 119–127.     

激光等离子体2660紫外探针及干涉系统

成功地在六路高功率Nd玻璃激光装置上建立了2660紫外激光探针和适合紫外波段的Normaski干涉仪,首次将可见波长的连续激光应用于紫外干涉仪中靶成像调整和光路准直。利用该紫外光干涉仪,在铜柱状靶(φ500μm)上测量了厚等离子体中高达0.6n。的电子密度。     

A Language for Teaching Discrete-event Simulation

Courses which teach discrete-event simulation are based on many different simulation languages. The requirements for a language to support teaching simulation are discussed. In particular, it is recommended that such languages separate into distinct modules those aspects of simulation which are taught as separate topics. Implementation of the separation is discussed. The SEESIM language, developed as a teaching aid, is described, and examples of its use are given. Straightforward use of SEESIM can be learned quickly, yet the language provides facilities for a staged introduction to advanced concepts of simulation.     

Quantum interference of electrons in disordered metals

Investigation of the galvanomagnetic properties of disordered metals in weak magnetic fields [r(H)?l, wherer(H) is the electron trajectory radius andl, the electron free path], proved to be one of the effective experimental methods of studying disordered metals. The phase difference between the interfering electron waves is affected by the presence of magnetic flux in the sample. One of the observable effects is the oscillatory magnetoresistanceK(H) of multiconnected samples predicted by Altshuleret al (1981). The period ofK(H) oscillations for the hollow cylinders, networks or chains with orifices cross-sections areasS isΔH=φ ₀/2S [whereφ ₀=hc/e]. The amplitude and the phase of the oscillations depend on the spin orbit interaction, the intensity of superconductive fluctuation etc. It should be noted that in small “mesoscopic” single loops the oscillations with the periodΔH?φ ₀/S were also observed recently (see also Altshuleret al 1987 included in this issue).     

用变形全息透镜实现变形分数傅里叶变换

利用一发散点光源和一束倾斜平行光制作出在两个垂直方向上具有不同焦距的变形全息透镜,且用此全息元件实现了变形分数傅里叶变换。变形全息透镜两个方向上的焦距随全息记录条件和再现条件而变化,分析了用这种全息透镜实现变形分数傅里叶变换的条件。实验表明,用该元件能够方便地实现任意级次的变形分数傅里叶变换。     

The effect of Erbium concentration on the optical spectrum of Erbium-doped fiber laser

We report an experimental observation of the influence of concentration of Er³⁺ ions in an Erbiumdoped silica fiber on the spectral characteristics of an erbium fiber laser. Our basic conclusion is that an increase of erbium concentration in the fiber results in the laser optical spectrum narrowing. We also discuss possible mechanisms responsible for this effect.     

On the variational representation of solutions to some quasilinear equations and systems of hyperbolic type on the basis of potential theory

We demonstrate a method that permits to obtain generalized solutions for some quasilinear equations and systems of hyperbolic type. The corresponding variational principle is constructed using the theory of equilibrium of a potential in an external field. Dedicated to the memory of B. M. Levitan Supported by RFBR grants Nos. 05-01-00522 and NSh-1551.2003.1, by Program No. 1 of the Branch of Mathematics, Russian Academy of Sciences, and by INTAS project No. 03-51-6637.     

Anisotropy of two-photon absorption in gallium selenide at 1064 nm

The Bridgman method is used to grow single crystals of ε-GaSe. The two-photon absorption (TPA) coefficient β was measured for especially un-doped crystals at room temperature for the ordinary o-ray (β_⊥) and extraordinary e-ray (β_∥) using single-wavelength excitation by a Nd:YVO₄ laser at 1.064 μm with a pulse duration of 10 ps and a repetition rate of 81 MHz. No large anisotropy was observed for the TPA coefficients between the two geometries. The TPA coefficients were found to be β_⊥ = 1.07 × 10⁻⁹ cm/W and β_∥ = 1.88 × 10⁻⁹ cm/W. It was found that doping slightly increases the TPA coefficient. The value of the TPA for crystals doped with 0.5 at.% of Tl is β_⊥ = 7.56 × 10⁻⁹ cm/W.