自调Q自锁模固体激光器

利用被动锁模激光器的锁模原理,结合自锁模固体激光器中等效快可饱和吸收体的特性,讨论了控制运转状态的自锁模动力学方程和速率方程,给出了自调Q自锁模的条件,以及自调Q周期与激光器结构和运转参数的关系,所得结论与实验结果有很好的一致性。     

用腔内半导体可饱和吸收镜钛宝石激光器中自锁模状态的实验研究

用可饱和吸收体镜(SESAM)的掺钛蓝宝石激光器能够稳定运转在三种不同的锁模状态,即可饱和吸收体被动锁模、孤子锁模加被动锁模和KLM锁模.分析了三种自锁模的机理和SESAM的作用.对SESAM实现KLM锁模的自启动机制进行了实验观察和讨论.从该激光器的KLM锁模状态,获得了小于18飞秒的锁模脉冲序列. 关键词： 半导体可饱和吸收镜 自锁模 钛宝石激光器     

时空分布的超短激光脉冲烧蚀电介质材料时等离子体的产生

若考虑聚焦平面内固定区域,脉冲空间分布可简化为一维问题.在此基础上,从脉冲的传输过程出发,本文分析了时空分布的超短激光脉冲与电介质材料相互作用时等离子体形成模式.在材料内部累积的能量与脉冲宽度、与空间相关的损伤区域、等离子体形成时间及其吸收系数有关.     

Mechanism and elimination of spectrum filtering in a high power mode-locked fibre laser witha free output coupler

The filtering mechanism of a free output coupler mode-locked laser based on large-mode-area photonic-crystal fibre is analysed. A filtering-soliton mode-locked laser with 495~fs pulse width and 21 nJ pulse energy is achieved. Another novel cavity configuration is established to eliminate the filtering effect. Pulses, each 457~fs in width and 16.5 nJ in energy, are obtained in a soliton-like regime. Pulses, each 387~fs in width and 15.8 nJ in energy, are also generated in a stretched pulse regime and could be dechirped to 119~fs externally to the cavity.     

Operation of Kerr-lens mode-locked Ti:sapphire laser in thenon-soliton regime

A Kerr-lens mode-locked Ti:sapphire laser operating in a non-soliton regime is demonstrated. Dispersive wave generation is observed as a result of third order dispersion in the vicinity of zero dispersion. The characteristics of the Ti:sapphire laser operating in a positive dispersion regime are presented, where the oscillator directly generates pulses with duration continuously tunable from 0.37~ps to 2.11~ps, and 36~fs pulses are achieved after extracavity compression. The oscillation is numerically simulated with an extended nonlinear Schr?dinger equation, and the simulation results are in good agreement with the experimental results.     

奇异谱分析用于提升双光梳激光测距精度

从含噪数据中提取信号从而提升数据采集系统精度是极为重要的问题.奇异谱分析(singular spectrum analysis,SSA)作为一种无参数频谱估计技术,广泛用于区分系统模型未知情况下的动态系统信号的复杂成分.本文应用SSA方法提取双光梳飞秒激光测距系统中的含噪时间序列的距离信息,数值仿真显示SSA方法可以从含有有色噪声的信号中提取距离信号.实验中,SSA方法成功地从含有量子噪声的测距信号中提取出激光与目标之间的距离信息,提取后的信号有13倍的精度提升.这种方法同样适用于高维信号,如基于飞秒激光测距的高精度、高速率表面形貌测量的图像提取.     

Numerical simulation for characterizing femtosecond optical pulses with the SPIDER algorithm

In this article based on the spectral phase interferometry for direct electric-field reconstruction (SPIDER), the femtosecond pulses with various phase characters are numerically simulated. The spectral phases and amplitudes of the transform-limited pulse, the linear chirped pulse, the cubic dispersion pulse, the quartic dispersion pulse, the self-phase modulation pulse and the pulses with the combination of different chirped characters are retrieved. These characterized pulses are applicable to the real-time measurement as samples for diagnosing the chirped characters of pulses quickly.