Atoms ionization by the simultaneous absorption of multiple photons has found applications in fiber optics, where it leads to unique nonlinear phenomena. To date, studies of the ionization regime have been limited to gas-filled hollow-core fibers. Here, we investigate multiphoton ionization of standard optical fibers, where intense laser pulses ionize the atoms constituting the fiber structure itself, instead of that of the filling gas. We characterize material modifications produced by optical breakdown. Their formation affects laser beam dynamics over hours long temporal scales. The damage features are studied by means of optical microscopy and X-ray microtomography. In the framework of glass photonics, our results pave the way for a novel glass waveguide micromachining technique.

中文翻译：

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标准光纤的多光子电离

通过同时吸收多个光子实现的原子电离已在光纤中得到应用，它会导致独特的非线性现象。迄今为止，对电离机制的研究仅限于充气中空纤维。在这里，我们研究了标准光纤的多光子电离，其中强激光脉冲电离了构成光纤结构本身的原子，而不是填充气体的原子。我们描述了由光击穿产生的材料改性。它们的形成会在数小时长的时间尺度上影响激光束动力学。通过光学显微镜和 X 射线显微断层扫描来研究损伤特征。在玻璃光子学的框架内，我们的结果为新型玻璃波导微加工技术铺平了道路。