光学学报, 2019, 39 (8): 0832001, 网络出版: 2019-08-07
纳秒超高斯型激光脉冲在C60分子介质中的反饱和吸收光限幅行为 下载: 883次
Reverse Saturable Absorption-Induced Optical Power Limiting Behavior of Nanosecond Hyper-Gaussian Laser Pulses in C60 Molecular Medium
超快光学 脉冲整形 反饱和吸收 光限幅 超高斯型激光脉冲 绝热近似 迟至时间坐标系 ultrafast optics pulse shaping reverse saturable absorption optical power limiting hyper-Gaussian laser pulse adiabatic approximation retarded time coordinate
摘要
利用克兰克-尼科尔森差分法求解激光场的傍轴波动方程和粒子数速率方程,研究纳秒超高斯型激光脉冲与富勒烯C60分子的相互作用过程,并模拟不同阶次强场超高斯型激光脉冲在介质中的传播演化情况。当强场超高斯脉冲在C60分子介质中传播时,表现出明显的反饱和吸收光限幅效应,而且脉冲的时空包络形状在传播过程中被重塑,由初始入射时的具有中心对称性的平顶型时间包络分布逐渐转变成具有非中心对称的尖顶型激光脉冲分布,而且脉冲持续时间也缩短了一个数量级;随着输入超高斯型脉冲时间阶次的不断增大,在传播过程中被吸收的脉冲不断增多,出射脉冲宽度逐渐减小。
Abstract
The interaction process between a nanosecond hyper-Gaussian laser pulse and a fullerene C60 molecular medium is studied by numerically solving the paraxial wave and particle rate equations through the hyper-Gaussian laser pulse Crank-Nicholson difference method. The evolution of the strong hyper-Gaussian laser pulse with different orders is simulated. Optical power limiting behavior caused by reverse saturable absorption is observed when the strong hyper-Gaussian pulse is propagating in the C60 molecular medium. The spatiotemporal shape of the hyper-Gaussian pulse can be obviously reshaped during propagation, and incident pulse with flat-topped time envelope distribution and central symmetry turns into the pulse with tip laser pulse distribution and asymmetry gradually. The pulse width decreases by an order of magnitude owing to the strong reverse saturable absorption of C60. Thus, the higher the order of the hyper-Gaussian pulse is, the more the reverse saturable absorption is, and the narrower the width of the output pulse is.
刘纪彩, 赵亚男, 张莹, 成飞. 纳秒超高斯型激光脉冲在C60分子介质中的反饱和吸收光限幅行为[J]. 光学学报, 2019, 39(8): 0832001. Jicai Liu, Yanan Zhao, Ying Zhang, Fei Cheng. Reverse Saturable Absorption-Induced Optical Power Limiting Behavior of Nanosecond Hyper-Gaussian Laser Pulses in C60 Molecular Medium[J]. Acta Optica Sinica, 2019, 39(8): 0832001.