论文标题
非线性镜头对超快激光脉冲与空心核波导的耦合的影响
The effect of nonlinear lensing on the coupling of ultrafast laser pulses to hollow-core waveguides
论文作者
论文摘要
充满气体的空心核纤维是通过各种非线性光学效应来操纵超快激光脉冲的灵活平台。初始脉冲的有效高保真耦合对于系统性能非常重要。在这里，我们研究了使用（2+1）二维数值模拟的超快激光脉冲偶联到空心核纤维中的自我关注对超快激光脉冲耦合的影响。正如预期的那样，我们发现耦合效率被降解，并且当入口窗口太近时，耦合脉冲的持续时间就会改变。非线性时空重塑和窗口的线性分散的相互作用会根据窗户材料，脉冲持续时间和脉冲波长产生不同的结果，其较长波长梁具有更高的窗口中高强度的耐受性。在将标称焦点转移以补偿的同时可以恢复一些损失的耦合效率，但仅略微提高脉冲持续时间。从我们的模拟中，我们为窗口和HCF入口方面之间的最小距离得出了一个简单的表达式。我们的结果对空心核纤维系统的经常空间约束的设计具有影响，尤其是在输入能量不恒定的情况下。
Gas-filled hollow-core fibres are a flexible platform for the manipulation of ultrafast laser pulses through a variety of nonlinear optical effects. Efficient high-fidelity coupling of the initial pulses is very important for system performance. Here we study the effect of self-focusing in gas-cell windows on the coupling of ultrafast laser pulses into hollow-core fibres using (2+1)-dimensional numerical simulations. As expected, we find that the coupling efficiency is degraded and the duration of the coupled pulses changed when the entrance window is too close to the fibre entrance. The interplay of nonlinear spatio-temporal reshaping and the linear dispersion of the window create different results depending on the window material, pulse duration, and pulse wavelength, with longer-wavelength beams more tolerant of high intensity in the window. While shifting the nominal focus to compensate can restore some of the lost coupling efficiency, it improves the pulse duration only marginally. From our simulations we derive a simple expression for the minimum distance between the window and the HCF entrance facet. Our results have implications for the often space-constrained design of hollow-core-fibre systems, especially where the input energy is not constant.
