光解CF3I研究I(52p1/2)的动力学

 本实验用YAG激光器的四倍频光,光解CF₃I得到I(5²P_1/2)。通过测量I(5²P_1/2)跃迁到基态而发出的1.315 μm荧光得到I(5²P_1/2)的自发辐射寿命为0.0370.005s,测得CF₃I、O₂、He对I(5²P_1/2)的猝灭常数分别为0.605Pa^-1s^-1,2 .25Pas^-1及0.22Pas^-1。     

0.35μm激光与金靶耦合发射X光能谱分析

 利用改进后的More模型计算Au等离子体各电离度离子的Einstein系数和线发射强度。在0.35μm激光与金平面靶耦合产生晕区等离子体条件下,求解离子模型定态速率方程组得到离子布居概率,从而求出X光线发射能谱。将此能谱与JB19程序计算得到的出系统外边界光子能谱进行了比较。     

In-Phase Wavelength Conversion Based On Cross-Gain Modulation in Semiconductor Optical Amplifier

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｃｒｏｓｓ ｇａｉｎｍｏｄｕｌａｔｉｏｎ (ＸＧＭ )ｉｎｓｅｍｉｃｏｎｄｕｃｔｏｒｏｐｔｉｃａｌａｍｐｌｉｆｉｅｒｓ (ＳＯＡｓ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｅｆｆｉｃｉｅｎｔｗａｙｓｔｏａｃｈｉｅｖｅａｌｌ ｏｐｔｉｃａｌｗａｖｅｌｅｎｇｔｈｃｏｎｖｅｒｓｉｏｎａｎｄｈａｓｓｉｍｐｌｅｉｍｐｌｅｍｅｎｔａｔｉｏｎ ,ｌａｒｇｅｗａｖｅｌｅｎｇｔｈｃｏｎｖｅｒｓｉｏｎｓｐａｎ ,ｈｉｇｈｃｏｎｖｅｒｓｉｏｎｅｆｆｉｃｉｅｎｃｙ[1] ａｎｄｅｘｔｒｅｍｅｌｙｈｉｇｈｂｉｔｒａｔｅ…     

原子相干性对 V型三能级原子自发辐射的影响

本文分别就两种模型,即三能级原子与单模场和双模场的V型相互作用,研究了原子相干性对原子自发辐射的影响.发现在单模情况,原子相干性导致原子自发辐射的消除;而在双模情况,两个跃迁通道的自发辐射是相互独立的,原子相干性不导致原子自发辐射的消除.     

紫外波段有机染料DMT掺杂SiO2薄膜的光谱特性

本文采用溶胶 凝胶法合成了紫外波段有机染料DMT掺杂SiO2 薄膜和块体材料 薄膜中掺杂浓度高达 1 2 4× 1 0 - 2 mol/L ,块体材料浓度掺至 1 5× 1 0 - 3mol/L 由于SiO2“笼”的束缚作用 ,在荧光光谱中未观察到荧光猝灭现象 ;由于SiO2 “笼”的极化作用 ,370nm的发射峰较其在环己烷中发生了 34～ 44nm左右的红移 ;580～ 590nm的发射峰的量子效率比 370nm的发射峰略高     

Prompt light particle emission in the 36Ar + 58Ni reaction at 95 MeV/nucleon

The prompt component at intermediate velocity of light charged particles is investigated. An improved coalescence model coupled to the intra-nuclear cascade code ISABEL is used to obtain light complex particle energy spectra and multiplicities as a function of impact parameter. The results are compared with experimental data from the ³⁶Ar + ⁵⁸Ni experiment at 95 MeV/nucleon, performed with the INDRA 4π detection system. The calculated prompt component is found to rather well reproduce proton spectra. For complex light charged particles the calculated components well populate the high energy part of spectra. Prompt emission can therefore explain the large transverse energies experimentally observed at mid-rapidity. Received: 27 July 2000 / Accepted: 20 November 2000     

High temperature (T>300 K) light emitting diodes for 8–12 μm spectral range

Contrary to conventional light emitting diodes for visible and very near infrared utilizing interband (ω>E_g) luminescence, the longer infrared emitting diodes (LIREDs) we describe here utilize intraband (ω<E_g) electron transitions and emit beyond the fundamental absorption range of the material used. Made of indirect band gap semiconductors (like Ge, Si) and, therefore, free from the Auger recombination impact, LIREDs efficiently operate at higher temperatures (T>300 K) in the longer wavelength atmospheric window (8–12 μm). Electrically modulated power emitted is comparable to that for black body sources whereas shorter rise–fall times are due to recombination processes (200 μs) and not dependent on pixel thermal mass and thermal conduction. LIREDs can be made of different semiconductor structures provided the controllable modulation of free carrier concentration in the device base is achieved. The main parameters of Ge based LIREDs under injection mode are reported.     

Inelastic tunneling in a double quantum dot coupled to a bosonic environment

Coupling a quantum system to a bosonic environment always give rise to inelastic processes, which reduce the coherency of the system. We measure energy-dependent rates for inelastic tunneling processes in a fully controllable two-level system of a double quantum dot. The emission and absorption rates are well reproduced by Einstein's coefficients, which relate to the spontaneous emission rate. The inelastic tunneling rate can be comparable to the elastic tunneling rate if the boson occupation number becomes large. In the specific semiconductor double dot, the energy dependence of the inelastic rate suggests that acoustic phonons are coupled to the double dot piezoelectrically.     

高强混凝土单轴压缩声发射频率特征试验研究

为研究高强混凝土破裂前声发射信号的频率特征,对C60、C70、C80高强混凝土试件进行单轴压缩下的高、低频双通道声发射试验,得到破裂过程的力学参数和声发射参数,探求高强混凝土不同加载阶段声发射信号频率的分布特征。研究表明,三种高强混凝土在峰值应力前,高、低频通道声发射信号均集中在特定的频段内;临近峰值应力时,高、低频通道的声发射信号频率向低频段移动,同时优势频段内的频率趋于分散,这可作为预测高强混凝土破坏的前兆信息。     

Rayleigh-Taylor不稳定性背光照相实验背光源初步理论研究

为开展中等功率激光器上Rayleigh-Taylor不稳定性背光照相实验,对多种背光源靶材料及其发射的K、L、M带X光谱强度作了数值模拟计算。计算结果表明,用数百焦耳倍频激光来产生能量为2keV左右的X光背光源是可能的。