标题： 基于自适应激光射击和$\textit{in situ}$成像的纤维基微镜轮廓控制 显示英文标题

标题： Profile control of fibre-based micro-mirrors using adaptive laser shooting with $\textit{in situ}$ imaging

摘要： 光纤法布里-珀罗腔（FFPCs）由于其模式体积小且与光纤具有紧凑的集成性，在腔量子电动力学（CQED）和量子技术的各种研究中被使用。 我们开发了一种新颖的$\text{CO}_2$激光加工方法，能够在切割光纤的端面产生可控的表面轮廓。 通过在不同空间分布模式下进行多次射击，我们的方法采用了一种射击算法，在射击过程中自适应地改变激光烧蚀参数，以抑制与期望轮廓的偏差。 这是通过$\textit{in situ}$对加工后的轮廓进行成像、检查，并在后续步骤中使用该信息来实现的。 该算法的基础是一种新发现的激光烧蚀参数，即两次射击之间的暂停时间，它控制着连续激光射击之间热量的积累，从而决定了单个烧蚀序列的影响区域。 我们制造了曲率半径从 250$\mu$m 到 700$\mu$m 的基于光纤的微镜，有效镜面直径为 60$\mu$m，可以是高斯或球形轮廓。 由于我们自适应算法的自我校正特性，我们在生产所需轮廓方面实现了接近 100% 的成功率，且椭圆度较低。 在对激光加工的光纤端面涂覆高反射率涂层后，形成了 FFPCs，在 854 nm 的光学波长下展示了高达 150,000 的精细度。 显示英文摘要

摘要： Fibre Fabry-Perot cavities (FFPCs) are used in various studies in cavity quantum electrodynamics (CQED) and quantum technologies due to the cavity's small mode volume and compact integration with optical fibres. We develop a novel $\text{CO}_2$ laser machining method that produces well-controlled surface profiles on the end facets of cleaved optical fibres. Using multiple shots in distinct spatial distribution patterns, our method employs a shooting algorithm that adaptively changes laser ablation parameters during the shooting to suppress deviations from the desired profile. This is made possible by $\textit{in situ}$ imaging of the machined profile, its inspection and the usage of the information in the subsequent steps. Underlying this algorithm is a newly found laser ablation parameter, the pause between shots, which controls the accumulation of heat in between successive laser shots and as a result determines the area of impact made by an individual ablation sequence. We fabricate fibre-based micro-mirrors with radii of curvature ranging from 250 $\mu$m to 700 $\mu$m with an effective mirror diameter of 60 $\mu$m in either Gaussian or spherical profiles. Due to the self-correcting nature of our adaptive algorithm, we achieve a near 100\% success rate in the production of desired profiles with low ellipticity. After furnishing the laser machined fibre end facets with high reflectivity coating, FFPCs are formed to demonstrate a high finesse up to 150,000 at an optical wavelength of 854 nm.