Enantioselective optical trapping of chiral nanoparticles by tightly focused fractional vector beams

Area of Science:

• Optics
• Chirality
• Nanotechnology

Background:

• Enantiomers, molecules with identical structures but different spatial arrangements, display distinct properties crucial in biomedicine and chemistry.
• Distinguishing and separating enantiomers remains a significant challenge in scientific research and industrial applications.

Purpose of the Study:

• To introduce a novel optical method for the selective trapping and manipulation of enantiomers.
• To demonstrate the capability of focused fractional vector beams (FVBs) in achieving precise control over chiral molecules.

Main Methods:

• Utilizing tightly focused fractional vector beams (FVBs) to generate localized optical chirality densities (OCDs) with alternating signs.
• Investigating the interaction between focused FVBs and enantiomers to achieve selective trapping based on molecular handedness.

Main Results:

• Focused FVBs can stably trap enantiomers at specific locations determined by the local optical chirality density (OCD) and the enantiomer's handedness.
• The number and positions of trapped enantiomers are controllable via the fractional topological charge of the FVBs.
• Demonstrated dynamic modulation and precise, stable trapping of multiple enantiomer pairs.

Conclusions:

• Tightly focused FVBs offer an all-optical solution for enantiomer manipulation, enabling dynamic control and precise trapping.
• The proposed method has significant potential for high-throughput and multi-sample manipulation of chiral materials in various scientific fields.