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排序方式: 共有158条查询结果,搜索用时 62 毫秒
71.
微腔激光器速率方程分析 总被引:1,自引:0,他引:1
推出了至少有一维尺寸在发射波长量级的微腔激光器的光输出特性,首次得到了无辐射衰减速率不等于零时速率方程的角析解。结果表明,微腔激光器自发发射到腔模的较高的合效率使激发特性和传统的激光器有很大的不同。 相似文献
72.
Pi-Tai Chou Chen-Pin Chang John H. Clements Kuo Meng-Shin 《Journal of fluorescence》1995,5(4):369-375
The synthesis and photophysics of 4-formyl-4-N,N-dimethylamino-1,1-biphenyl are reported. The emission spectrum in various solvent polarities demonstrates solvatochromism, indicating that the fluorescence originates from an electronically excited species with a strong charge transfer character. The change in
[
max(absorption) –
max(emission)] varies from 1500 cm–1 inn-heptane to as much as 7500 cm–1 in acetonitrile. In protic solvents, the unusual excitation energy-dependent steady-state emission (red edge effect), resulting from solvent dielectric relaxation, was observed in media with a low viscosity. The large Stokes-shifted and high-yield fluorescence led to the observation of the efficient lasing action. The frequency tunability of the laser output is strongly solvent dependent, generating a new charge transfer laser dye in the blue-green region. 相似文献
73.
Tim Plath Philipp Amstutz Jörn Bödewadt Günter Brenner Nagitha Ekanayake Bart Faatz Kirsten Hacker Katja Honkavaara Leslie Lamberto Lazzarino Christoph Lechner Theophilos Maltezopoulos Matthias Scholz Siegfried Schreiber Mathias Vogt Johann Zemella Tim Laarmann 《Journal of synchrotron radiation》2016,23(5):1070-1075
Free‐electron lasers (FELs) generate femtosecond XUV and X‐ray pulses at peak powers in the gigawatt range. The FEL user facility FLASH at DESY (Hamburg, Germany) is driven by a superconducting linear accelerator with up to 8000 pulses per second. Since 2014, two parallel undulator beamlines, FLASH1 and FLASH2, have been in operation. In addition to the main undulator, the FLASH1 beamline is equipped with an undulator section, sFLASH, dedicated to research and development of fully coherent extreme ultraviolet photon pulses using external seed lasers. In this contribution, the first simultaneous lasing of the three FELs at 13.4 nm, 20 nm and 38.8 nm is presented. 相似文献
74.
利用金属有机物气相沉积技术(MOCVD)在(0001)蓝宝石衬底上生长了Ga N基垂直腔面发射激光器(VCSEL)的多量子阱腔层结构。X射线衍射测量显示该多量子阱具有良好周期结构和平整界面。运用键合及激光剥离技术将该外延片制作成VCSEL,顶部和底部反射镜为极高反射率的介质膜分布布拉格反射镜(DBR)。在室温、紫外脉冲激光的泵浦条件下,观察到了VCSEL明显的激射现象,峰值波长位于447.7 nm,半高宽为0.11 nm,自发辐射因子约为6.0×10-2,阈值能量密度约为8.8 m J/cm2。在大幅度降低制作难度的情况下,得到目前国际最好结果同样数量级的激射阈值。降低器件制作难度有利于制备的重复性,有利于器件的产品化。 相似文献
75.
76.
Andrea Camposeo Marco Polo Pompilio Del Carro Leonardo Silvestri Silvia Tavazzi Dario Pisignano 《Laser \u0026amp; Photonics Reviews》2014,8(5):785-791
The simultaneous vertical‐cavity and random lasing emission properties of a blue‐emitting molecular crystal are investigated. The 1,1,4,4‐tetraphenyl‐1,3‐butadiene samples, grown by physical vapour transport, feature room‐temperature stimulated emission peaked at about 430 nm. Fabry‐Pérot and random resonances are primed by the interfaces of the crystal with external media and by defect scatterers, respectively. The analysis of the resulting lasing spectra evidences the existence of narrow peaks due to both the built‐in vertical Fabry‐Pérot cavity and random lasing in a novel, surface‐emitting configuration and threshold around 500 μJ cm−2. The anti‐correlation between different modes is also highlighted, due to competition for gain. Molecular crystals with optical gain candidate as promising photonic media inherently supporting multiple lasing mechanisms. 相似文献
77.
78.
数值计算具有自发辐射诱导相干性的开放V型三能级原子系统密度矩阵运动方程,分析无反转激光(LWI)增益的瞬态演化.结果表明:无论是否存在非相干抽运,探测场和驱动场间的相对位相(Ф)对增益的瞬态演化都有显著的影响;通过选择的取值可以获得更大的瞬态和稳定增益;不存在非相干抽运时,系统达到瞬态增益最大值及获得增益稳定值所需要的时间更长,演化过程中振荡幅度更大,获得的增益更大;原子退出速率r0(原子注入速率比S)的变化将使增益瞬态演化的具体过程发生改变,在r0(S)的一定取值范围内,瞬态和稳定增益随S(r0)的增大而增大. 相似文献
79.
Ye TianXiangyang Ma Luelue XiangM.V. Ryzhkov A.A. BorodkinS.I. Rumyantsev Deren Yang 《Optics Communications》2012,285(24):5323-5326
We have investigated the optically and electrically pumped random lasing (RL) actions in ZnO films annealed at low and high temperatures respectively. While the optically pumped RL threshold for the ZnO film annealed at a low temperature, which features stronger light scattering and larger optical loss, is far higher than that for the ZnO film annealed at a high temperature, the electrically pumped RL threshold currents for the two ZnO films are almost the same with the electrical pumping scheme of metal-insulator-semiconductor structure. It is suggested that if the lasing region within the ZnO film is narrow enough in the case of electrical pumping, the strong light scattering can substantially alleviate the adverse effect of large optical loss on the onset of RL. 相似文献