Nano Lett. 2018 Oct 10;18(10):6509-6514. doi: 10.1021/acs.nanolett.8b03033. Epub 2018 Sep 7.
The optical reshaping of metallic nanostructures typically requires intense laser pulses to first approach or achieve melting, followed by surface-tension-dominated reshaping, transforming the original nanostructures into more spherical morphologies. Here, we report the directional optical reshaping of the Au nanodisk of an Al-Au heterodimer in the illuminated junction of an atomic force microscope (AFM). Both the heightening and the repositioning of the Au nanodisk component are induced, reducing the gap between the two nanodisks. There are three contributors to this process: the photothermal softening of the Au lattice, the optical force applied to the Au nanodisk by the Al nanodisk, and the optical force from the nearby AFM tip. The asymmetric reshaping of the heterodimer is observable structurally, through electron microscopic imaging, and through changes in the heterodimer optical response. This optical-force-directed shape manipulation may have potential applications in nanofabrication, optically induced nanomanufacturing, sensing, and quality control.
金属纳米结构的光整形通常需要强激光脉冲首先接近或达到熔化，然后是由表面张力主导的整形，将原始纳米结构转变为更球形的形态。在这里，我们报告了在原子力显微镜（AFM）的照射结处，对 Al-Au 异质二聚体中的 Au 纳米盘进行定向光整形。Au 纳米盘组件的升高和重新定位都被诱导，从而减小了两个纳米盘之间的间隙。这个过程有三个贡献者：Au 晶格的光热软化、Al 纳米盘施加在 Au 纳米盘上的光力，以及附近 AFM 尖端的光力。通过电子显微镜成像和异质二聚体光学响应的变化，可以观察到异质二聚体的不对称整形。这种光力导向的形状操纵可能在纳米制造、光诱导纳米制造、传感和质量控制方面有潜在的应用。
