Figure 1: Principle of helicity-dependent optical trapping.
From: Helicity-dependent three-dimensional optical trapping of chiral microparticles
A chiral object with chirality χ=±1 is trapped, or not, at the location O, by a light field with helicity Λ=±1. The non-restoring (a,d) or restoring (b,c) nature of the optical force F, hence the stability of the optical trap, depends on the sign of the product of the helicity of light and the chirality of matter.
