提出并演示了利用宽束离子束刻蚀方法一次性对多个杠铃形金属纳米结构进行“横向抽减”，形成极小纳米间隙，从而实现多个金属纳米间隙结构的快速加工。利用电子束曝光定义图形化抗蚀剂结构，通过传统的金属沉积和湿法剥离将抗蚀剂图案转移至杠铃形金属纳米结构，最后使用宽束离子束刻蚀进行修剪。实验表明，精确控制刻蚀时间可以使杠铃形结构的两个纳米天线间的间隙距离达到10 nm以下，通过结合基于HSQ负性抗蚀剂的图案化工艺，可在HSQ纳米模板上制得悬空金属纳米间隙结构。利用表面结构形貌表征获得刻蚀过程中纳米结构的形态演变规律，并通过系统的实验和模拟验证了悬空金属间隙结构用于表面增强拉曼散射的优势。该方案为多个极小金属纳米间隙结构的一次成型提供了新的思路，在大面积拉曼传感衬底的低成本高效制备方面具有可观的应用前景。

Nanogap plasmonic structures with strong coupling between separated components have different responses to orthogonal-polarized light, giving rise to giant optical chirality. Here, we proposed a three-dimensional (3D) nanostructure that consists of two vertically and twistedly aligned nanogaps, showing the hybridized charge distribution within 3D structures. It is discovered that the structure twisted by 60° exhibits plasmonic coupling behavior with/without gap modes for different circular-polarized plane waves, showing giant chiral response of 60% at the wavelength of 1550 nm. By controlling the disk radius and the insulator layer, the circular dichroism signal can be further tuned between 1538 and 1626 nm.