负曲率空芯光纤对飞秒超短脉冲光的压缩研究

为了实现对飞秒激光器产生的超短脉冲的进一步压缩,对近年来出现的一种新型负曲率空芯光纤展开了研究,并基于该光纤对800 nm飞秒激光进行了压缩实验。首先介绍了一种圆形玻璃管包层结构的负曲率空芯光纤,通过有限元方法对光纤的损耗特性进行计算,并与实验测试结果进行对比。然后利用广义非线性薛定谔方程对脉冲在光纤中的传输进行了模拟仿真。最后利用该光纤进行了超短脉冲压缩实验,将脉冲宽度为160 fs的钛宝石飞秒激光耦合进一段充高压氩气的圆形玻璃管包层结构的负曲率空芯光纤,通过光纤内反常色散和自相位调制的共同作用,得到84 fs的输出,实现脉冲的压缩,实验结果与仿真计算一致。这种新型的负曲率空芯光纤损伤阈值高、色散、非线性系数小且灵活可调,非常适用于超快领域研究。

Femtosecond pulse compression using negative-curvature hollow-core fibers

In order to compress femtosecond ultrashort pulses, a novel fiber called negative-curvature hollow-core fiber, is investigated and is used to compress the output of a Ti:Sapphire laser. Firstly, a hollow-core fiber with circular tubes cladding is introduced, and the loss parameter is calculated with the Finite Element Method and the calculated results are compared with the experimental results. Following this, the evolution of an ultrashort pulse along the fiber is simulated in the General Nonlinear Schrodinger Equation. At last the compression experiment using NC-HCF is conducted. The 160 fs output of a Ti:Sapphire laser is coupled into the fiber with high-pressure Argon. An output of 84 fs is achieved, which is the result of the balance between anomalous dispersion and self-phase modulation in the fiber. The experimental results matched the simulations. This novel fiber, which has the advantages of a high damage threshold, low and adjustable dispersion and nonlinear coefficients, is a promising material in the field of ultrafast optics.