High-rate direct femtosecond (fs) laser writing is a well-established technology for fabricating various micro-optical elements in bulk dielectrics. In this technology, the “heat accumulation” effect, occurring during high-repetition rate (∼ 1 MHz) exposure in dielectrics by a fs laser, enables ultralow-energy micro-modification via cumulative heating. Meanwhile, in this work in the transient multi-photon A-band photoluminescence studies, we demonstrate that this effect underlies dynamic thermal lensing even in diamond with its high thermal conductivity, dynamically shifting the laser focus upstream. Our study paves the way for more precise, accurate and robust direct fs-laser writing of advanced three-dimensional structures in diamond and other dielectrics for a variety of photonic applications.

中文翻译：

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通过瞬态 A 波段光致发光设想的块状金刚石中亚兆赫率飞秒激光脉冲的累积散焦

高速直接飞秒 (fs) 激光写入是一种成熟的技术，用于在体电介质中制造各种微光学元件。在这项技术中，fs 激光在电介质中以高重复频率（~1 MHz）暴露期间发生的“热量积累”效应通过累积加热实现了超低能量微改性。同时，在瞬态多光子 A 波段光致发光研究的这项工作中，我们证明了即使在具有高热导率的金刚石中，这种效应也是动态热透镜效应的基础，动态地将激光焦点向上游移动。我们的研究为更精确、准确和稳健的直接 fs 激光写入金刚石和其他电介质中的先进三维结构铺平了道路，用于各种光子应用。