Zheng Hongxia, Li Xiao, Ng Jack, Chen Huajin, Lin Zhifang
Opt Lett. 2020 Aug 15;45(16):4515-4518. doi: 10.1364/OL.398216.
Based on the concepts of conservative and non-conservative optical forces (COF and NCOF), we analyze the physical mechanism of longitudinal chirality sorting along the direction of light propagation in some simple optical fields. It is demonstrated, both numerically and analytically for particle of arbitrary size, that the sorting relies solely on the NCOF, which switches its direction when particle chirality is reversed. For particles larger than half of the optical wavelength , the NCOF far surpasses its counterpart COF, enabling the longitudinal chirality sorting. When the particle is much smaller than , however, the COF outweighs the NCOF, destroying the sorting mechanism. A scenario is thus proposed that totally eliminates the COF while leaving the sorting NCOF unchanged, extending the applicability of longitudinal chirality sorting to small particles.
基于保守和非保守光学力（COF和NCOF）的概念，我们分析了在一些简单光学场中沿光传播方向进行纵向手性分选的物理机制。对于任意尺寸的粒子，通过数值和解析方法都证明，这种分选仅依赖于NCOF，当粒子手性反转时，NCOF会改变其方向。对于大于光学波长一半的粒子，NCOF远超过其对应的COF，从而实现纵向手性分选。然而，当粒子比波长小得多时，COF超过NCOF，破坏了分选机制。因此提出了一种方案，即完全消除COF，同时保持分选NCOF不变，从而将纵向手性分选的适用性扩展到小粒子。
