Chirality-assisted lateral momentum transfer for bidirectional enantioselective separation

• 作者: Yuzhi Shi Tongtong Zhu Tianhang Zhang Alfredo Mazzulla Din Ping Tsai Weiqiang Ding Ai Qun Liu Gabriella Cipparrone Juan JoséSáenz Cheng-Wei Qiu
• 来源期刊: 光：科学与应用（英文版）
• 年，卷（期）: 2020,（3）
• 所属期刊栏目: Original Articles
• 页码范围: 645-656
• 页数: 12页
• 语种: 英文

摘要

Lateral optical forces induced by linearly polarized laser beams have been predicted to deflect dipolar particles with opposite chiralities toward opposite transversal directions. These"chirality-dependent"forces can offer newpossibilities for passive all-optical enantioselective sorting of chiral particles, which is essential to the nanoscience and drug industries. However, previous chiral sorting experiments focused on large particles with diameters in the geometrical-optics regime. Here, we demonstrate, for the first time, the robust sorting of Mie (size～wavelength) chiral particles with different handedness at an air–water interface using optical lateral forces induced by a single linearly polarized laser beam. The nontrivial physical interactions underlying these chirality-dependent forces distinctly differ from those predicted for dipolar or geometrical-optics particles. The lateral forces emerge from a complex interplay between the light polarization, lateral momentum enhancement, and out-of-plane light refraction at the particle-water interface. The sign of the lateral force could be reversed by changing the particle size, incident angle, and polarization of the obliquely incident light.