Photo-induced Enantiomeric Separation on chip

ongoing

Separating the two enantiomeric versions of a chiral molecule is crucial for ensuring the safety of pharmacological drugs and agrochemicals for the human body and the environment. However, the enantiomeric separation process at industrial level through chiral chromatography is costly and slow. As a result, 90% of chiral pharmaceutical drugs and agrochemicals are being sold as racemic mixtures. The PiEs-on-chip project aims at exploiting enantio-selective optical forces produced in silicon-based Photonic Integrated Circuits (PICs) to separate enantiomers. The chiral light-matter interaction, between the light guided throughout the PIC and the enantiomers results in a momentum transfer due to optical forces that move the particles of opposite chirality in opposite directions, leading to their Photo-induced Enantiomeric Separation (PiES). The PIC would be easy to mass-produce at low cost per device, thus, making optical enantiomeric separation more viable at industry level. Guided modes along integrated rectangular waveguides demonstrated inherent transversal and/or longitudinal spin which generates chiral optical forces that could be used for separating chiral particles in the transversal and/or longitudinal direction. Although the use of silicon-based waveguides is promising, they still lack more strength in the optical forces that can exert on smaller particles like molecules, partially due to the simple designs of the tested PICs. This requires new strategies to enhance enantio-selective interactions. The PiES-on-chip novel approach consists in inversely designing the PIC with topology optimization with the objective of maximizing the produced enantio-selective optical forces. Next, we will fabricate the optimized PIC and measure the generated chiral optical forces with Photo-induced Force Microscopy. Finally, we will deliver the chiral particles over the PIC with a microfluidic layer and experimentally verify the laser-driven enantiomeric-separation on chip.