论文标题
通过在充满氢的空心芯纤维中的chirp辅助拉曼散射以1.8μm的1.8μm生成低于40的FS脉冲
Generation of sub-40 fs pulses at 1.8 μm by chirp-assisted Raman scattering in hydrogen-filled hollow-core fibre
论文作者
论文摘要
在分子指纹区域进行时间分辨的光谱研究的可能性或扩展高谐波产生的截止波长，最近促进了有效的中红外超快激光的发展。特别是，基于活性培养基（例如Thulium或Hounmium）的纤维激光器是一个非常活跃的研究领域，因为它们是健壮的，紧凑的，并且可以以高的重复速率运行。但是，这些系统仍然很复杂，无法短于100 fs的脉冲，并且尚未像近红外对应物一样成熟。在这里，我们报告以1.8微米为单位的40 fs脉冲的产生，量子效率为50％，无需后压缩，在充满氢的空心光子光子晶体纤维中，由1030 nm的商用300-FS纤维激光器泵送。这是通过调节泵脉冲的轰动以及避免抑制拉曼增益的压力来实现的，并避免了泵脉冲的轰动以及发射到纤维中的高阶模式的比例。该系统是使用物理模型进行了优化的，该物理模型包含对光学响应的主要线性和非线性贡献。该方法是平均功率尺度的，可以调整脉冲形状，并有可能允许访问更长的波长。
The possibility of performing time-resolved spectroscopic studies in the molecular fingerprinting region or extending the cut-off wavelength of high-harmonic generation has recently boosted the development of efficient mid-infrared ultrafast lasers. In particular, fibre lasers based on active media such as thulium or holmium are a very active area of research since they are robust, compact and can operate at high repetition rates. These systems, however, are still complex, are unable to deliver pulses shorter than 100 fs and are not yet as mature as their near-infrared counterparts. Here we report generation of sub-40 fs pulses at 1.8 microns, with quantum efficiencies of 50% and without need for post-compression, in hydrogen-filled hollow-core photonic crystal fibre pumped by a commercial 300-fs fibre laser at 1030 nm. This is achieved by pressure-tuning the dispersion and avoiding Raman gain suppression by adjusting the chirp of the pump pulses and the proportion of higher order modes launched into the fibre. The system is optimized using a physical model that incorporates the main linear and nonlinear contributions to the optical response. The approach is average power-scalable, permits adjustment of the pulse shape and can potentially allow access to much longer wavelengths.
