反向光纤耦合器反向隔离特性研究

高功率窄线宽光纤激光器具有线宽非常窄,相干长度非常长等独特激光特性,目前广泛应用于材料加工,生物医疗等各个领域.反向光纤耦合器是高功率窄线宽光纤激光器核心光纤器件,反向光纤耦合器普遍采用端面泵浦耦合技术制备,其在高功率窄线宽光纤激光器实际应用过程中,对反向光纤耦合器反向隔离度特性的研究可以提高对泵浦光源的保护作用.主要...     

Alq/DCM薄膜中的放大自发发射

自从在以 8-羟基喹啉铝 (Alq)掺杂小分子激光染料 DCM为激活介质的波导结构中 [1] ,光泵浦下观察到激光现象以来 ,这种以高效发光有机半导体材料代替以往的溶胶、凝胶或透明聚合物材料来稀释激光染料的方法 ,引起了人们广泛的关注和巨大的兴趣。因为 Alq的发射谱和 DCM的激发谱有很大的重叠 ,所以经光泵浦后的 Alq∶ DCM薄膜中处于激发态的 Alq分子很容易与附近的 DCM分子形成能量迁移[1] ,从而其发射谱表现为 DCM的荧光谱 ,而不是 Alq和 DCM的荧光谱的简单叠加。由于材料的发射谱相对于激发谱红移很大 ,所以很大程度上降低了材料…     

Practical Laser Linewidth Limit

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5.4-TW/46-fs 10-Hz Ti:sapphire laser system

We have developed a compact Ti: sapphire laser system which can generate 5.4-TW pulses at 10-Hz repetition rate. Chirped-pulses are amplified to 450 mJ by a regenerative amplifier, a 4pass amplifier and a 3-pass amplifier. After compression, 250-mJ, 46-fs pulses are obtained     

Line profile study from diode laser spectroscopy in the CH4 2ν3 band perturbed by N2, O2, Ar, and He

We present a line profile study for two lines in the 2ν₃ band of CH₄ recorded with a frequency stabilized tunable diode laser spectrometer. The broadening and narrowing (Dicke effect) parameters of the R(0) line perturbed by N₂, O₂, and He are derived from a simultaneous fitting of spectra at pressures from 20 to 300 Torr by using the soft and hard collision models. These parameters are determined for the A and F components of the unresolved R(3) manifold perturbed by N₂, Ar, and He from the line profile analysis of spectra at pressures between 50 and 500 Torr. The line mixing effect between the two F components is also taken into account and the absorber speed dependent effect on broadening is estimated for N₂ and Ar.     

光抽运双光子激光的全量子理论

本文采用均匀加宽的四能级原子模型与光泵双光子激光相互作用,其系统具有双光子损耗机制。利用全量子理论推导各原子算符的朗之万方程,进而研究了稳态光子数、频率、线宽及激光运转过程。     

利用自差法研究激光二极管泵浦Nd:YVO_4激光器的线宽

用光纤延时自差法测量二极管激光纵向泵浦单频运转的Nd：YVO4激光器的线宽。在1秒时间内，激光线宽为25kHz。还测量了线宽与激光器腔长和输出功率的关系。     

Investigation of molecular motions of crosslinked polyepichlorohydrin by nuclear magnetic resonance spectroscopy

The molecular motion of crosslinked polyepichlorohydrin (PECH) is studied qualitatively by NMR techniques. The results of temperature dependence of ¹H T₂ and T₁ indicate that the crosslinking (crosslink density < 3%) restricts molecular motions of the polymer even far above its T_g. The ¹H T₁ minimum, corresponding to the large-scale chain-motion of crosslinked PECH, shifts to higher temperatures with increasing crosslink density. ¹H T₂ data also show that the crosslinking hinders free chain motions of the polymer above its T_g. The ¹³C T₁ relaxation time is sensitive to such motional changes as well. ¹³C linewidths of crosslinked PECHs vary with the crosslink density in both the swollen state and the solid state. The mechanism of ¹³C linewidth broadening of crosslinked polymers is discussed in detail. In the case of PECH, the linewidth broadening is caused by changing molecular environment due to crosslinking (such as presence of various chemical shift structures and freezing effects in conformational environment as chain mobility decreases), rather than increasing correlation times, which shorten the relaxation time (T₂) of polymer chains. © 1994 John Wiley & Sons, Inc.     

纳米尺寸CdS半导体微晶的光致发光线宽宽化研究

测量了各种温度下玻璃中掺杂纳米尺寸CdS半导体微晶的光致发光光谱,研究了其光致发光带的峰值能量和线宽对温度的依赖关系.考虑CdS微晶的LO声子的相互作用,拟合了其带隙发光带的线宽随温度的变化曲线,获得样品的非均匀线宽.CdS微晶的非均匀线宽主要是由于微晶的尺寸分布引起的.     

Mode Amplification in Inhomogeneous QD Semiconductor Optical Amplifiers

We present modelling results investigating the carrier dynamics of an SOA composed of an inhomogeneous array of quantum dots designed to produce broad gain amplification when optically pumped. We use a set of rate equations that describe the QDs inhomogeneity and include an energy dependent occupation factor within each inhomogeneously broadened level and numerically solve them with the propagation equation to investigate the amplification of optical signals in the waveguide. By treating the carrier filling according to the quasi-equilibrium distribution, we are able to investigate the effect of band-filling (BFE) on the gain and refractive index. The linewidth enhancement factor (α) is computed and analysed with respect to optical signal intensity as well as electrical current density.