论文标题
使用元表面进行冲击激发并聚焦在微观上
High-power laser beam shaping using a metasurface for shock excitation and focusing at the microscale
论文作者
论文摘要
在激光引起的强烈冲击波激发方面达到高可重复性和效率仍然是一个重大的技术挑战,这证明了大型国家实验室所做的广泛努力,以优化光元素颗粒的压缩。在这项研究中,我们提出并建模一种新型的光学设计,用于在桌面尺度上产生强烈的冲击。我们的方法利用了多个激光脉冲的空间和时间形状,以在凝结物质样品上形成同心激光环。每个激光环都会启动二维聚焦冲击波,该冲击波在环内的中央点与先前的冲击波重叠并收敛。我们提出了单个环配置的初步实验结果。为了使高功率激光聚焦在微米尺度上,我们在实验上证明了使用具有特殊损坏阈值的介电元面积的可行性,实验确定为1.1 j/cm2,作为常规选项的替代方法。这些元信息可以创建原始的,高弹性激光环,对于在材料中发射稳定的冲击波必不可少。在此,我们展示了使用水样品获得的结果,并在Gigapascal(GPA)范围内达到了冲击压力。我们的发现为在微观尺度上的凝结物质中应用激光诱导的强烈冲击压缩提供了一种有希望的途径。
Achieving high repeatability and efficiency in laser-induced strong shock wave excitation remains a significant technical challenge, as evidenced by the extensive efforts undertaken at large-scale national laboratories to optimize the compression of light element pellets. In this study, we propose and model a novel optical design for generating strong shocks at a tabletop scale. Our approach leverages the spatial and temporal shaping of multiple laser pulses to form concentric laser rings on condensed matter samples. Each laser ring initiates a two-dimensional focusing shock wave that overlaps and converges with preceding shock waves at a central point within the ring. We present preliminary experimental results for a single ring configuration. To enable high-power laser focusing at the micron scale, we demonstrate experimentally the feasibility of employing dielectric metasurfaces with exceptional damage threshold, experimentally determined to be 1.1 J/cm2, as replacements for conventional optics. These metasurfaces enable the creation of pristine, high-fluence laser rings essential for launching stable shock waves in materials. Herein, we showcase results obtained using a water sample, achieving shock pressures in the gigapascal (GPa) range. Our findings provide a promising pathway towards the application of laser-induced strong shock compression in condensed matter at the microscale.