Enantioselectivity in Chiral Crystallization Driven by the Canonical and Spin Momentum Forces of Optical Vortex Beams

Chiral perturbation can affect chiral crystallization, wherein achiral molecules form a chiral crystal, leading to an imbalance of the induction between two chiral crystals. Chiral light, such as circularly polarized light, represents a promising chiral perturbation that is versatile and does not necessitate any chemical additives. Laguerre-Gaussian (LG) beams, characterized by their helical wavefront carrying out the orbital angular momentum and spin angular momentum if circularly polarized, engender a distinctive interplay between canonical and spin momenta. This interplay results in the generation of exotic optical forces at the laser beam focus. In this study, a focused LG beam is employed to induce the chiral crystallization of ethylenediamine sulfate and to control the chirality of the resulting crystals. Intriguingly, experimental results reveal that the most significant enantioselectivity is achieved with a linearly polarized LG beam. Additionally, the tendency of the enantioselectivity varies based on the circular polarization of the LG beam. The asymmetry in light-matter interactions is examined by adjusting the laser power and varying the polarization of incident light. Our findings suggest that effective control over the crystal chirality of diverse materials could be attained through the interplay between the helicity of optical forces arising from the focused incident laser beam. This insight holds promising prospects for applications in biomolecules and nanocomposites, particularly in the pharmaceutical industry.