用于增强激光材料加工的受钻头启发的动态焦场
Drill-bit-inspired dynamic focal fields for augmented laser materials processing
AI总结：
研究受钻头启发的动态焦场用于激光材料加工，通过结合圆柱矢量光束与旋转矢量偏振滤波创建可旋转且能按需重新配置的焦点，建立两种工作模式并推导相关参数描述，实现低功率金属加工等多种效果，拓展了激光加工方式。
AI中文摘要：
激光制造通过对功率、脉冲持续时间、重复率和扫描轨迹的日益精确控制而取得进展，但光束的空间强度分布在光与物质相互作用期间通常仍是固定的。这一限制影响了能量传递到物质的方式，特别是在熔体流动、材料去除和表面形态在相当的时间和长度尺度上演变的过程中。本文引入受钻头启发的激光束，将焦点强度分布从被动、静态光斑转变为主动、可编程的加工工具。通过将圆柱矢量光束与旋转矢量偏振滤波相结合，创建了一个近衍射极限的双瓣厄米 - 高斯焦点，它围绕传播轴连续旋转且可按需重新配置。建立了动态光束旋转和瞬时光束轮廓移动两种工作模式，并推导了由沿扫描间距\(l = u/f\)（其中\(u\)是扫描速度，\(f\)是旋转频率）控制的累积能量密度和有效脉冲数的闭式描述。在连续波和超短脉冲模式下，这种动态能量沉积实现了低功率金属加工，钻孔效率比静态高斯光束高约四倍，增强了对流熔体流动，促进了小孔焊接中的气孔吸收并减少了残留气孔，还将简单的线性扫描转变为可编程表面纹理。这些结果表明，动态焦点轮廓控制可将激光加工扩展到静态光束整形之外，为制造中的可编程能量沉积开辟了广泛适用的途径。
英文摘要：
Laser manufacturing has advanced through increasingly precise control of power, pulse duration, repetition rate and scan trajectory, yet the spatial intensity profile of the beam is still usually fixed during light-matter interaction. This constraint limits how energy can be delivered to matter, particularly in processes where melt flow, material removal and surface morphology evolve on comparable time and length scales. Here we introduce drill-bit-inspired laser beams that convert the focal intensity distribution from a passive, static spot into an active, programmable processing tool. By combining cylindrical vector beams with rotational vectorial polarization filtering, we create a near diffraction limited two lobe Hermite-Gaussian focus that continuously spins about the propagation axis and can be reconfigured on demand. We establish two operating regimes, dynamic beam spinning and instantaneous beam-profile shifting, and derive closed-form descriptions of the accumulated fluence and effective pulse number governed by the along-scan pitch l = u/f, where u is the scan speed and f is the spin frequency. Across continuous-wave and ultrashort-pulse regimes, this dynamic energy deposition enables low-power metal machining with drilling efficiencies about four times higher than static Gaussian, enhances convective melt flow, promotes pore resorption and reduces retained porosity in keyhole welding, as visualized by in situ X-ray imaging, and turns simple linear scans into programmable surface textures. These results show that dynamic focal-profile control can extend laser processing beyond static beam shaping, opening a broadly applicable route to programmable energy deposition in manufacturing.
