Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan.
Nano Lett. 2012 Jul 11;12(7):3645-9. doi: 10.1021/nl301347j. Epub 2012 Jun 14.
We discovered for the first time that light can twist metal to control the chirality of metal nanostructures (hereafter, chiral metal nanoneedles). The helicity of optical vortices is transferred to the constituent elements of the irradiated material (mostly melted material), resulting in the formation of chiral metal nanoneedles. The chirality of these nanoneedles could be controlled by just changing the sign of the helicity of the optical vortex. The tip curvature of these chiral nanoneedles was measured to be <40 nm, which is less than 1/25th of the laser wavelength (1064 nm). Such chiral metal nanoneedles will enable us to selectively distinguish the chirality and optical activity of molecules and chemical composites on a nanoscale and they will provide chiral selectivity for nanoscale imaging systems (e.g., atomic force microscopes), chemical reactions on plasmonic nanostructures, and planar metamaterials.
我们首次发现，光可以扭曲金属以控制金属纳米结构的手性（以下简称手性金属纳米针）。光涡旋的螺旋性被传递到被照射材料的组成元素（主要是熔化的材料），从而形成手性金属纳米针。这些纳米针的手性可以通过改变光涡旋的螺旋性的符号来控制。这些手性纳米针的尖端曲率被测量为 <40nm，这小于激光波长（1064nm）的 1/25。这种手性金属纳米针将使我们能够在纳米尺度上选择性地分辨分子和化学复合材料的手性和旋光性，并为纳米尺度成像系统（例如原子力显微镜）、等离子体纳米结构上的化学反应和平面超材料提供手性选择性。
