Multiplexed Near-Field Optical Trapping Exploiting Anapole States.

Area of Science:

• Nanophotonics
• Biophysics
• Optical Engineering

Background:

• Optical tweezers are crucial for high-accuracy bioscience research, primarily focusing on individual particle manipulation.
• Studying biological heterogeneity necessitates methods for analyzing variations within populations.
• Current optical trapping methods face challenges in multiplexing at the nanoscale.

Purpose of the Study:

• To demonstrate a resonant metasurface capable of high-throughput, parallel optical trapping of nanoscale particles.
• To enable large-scale multiplexed optical trapping for studying biological heterogeneity.
• To overcome limitations in nanoscale multiplexing for optical tweezers.

Main Methods:

• Experimental demonstration of a resonant metasurface utilizing an anapole state for enhanced light-matter interaction.
• Utilizing the anapole state's angle tolerance for efficient excitation with focused light beams.
• Applying the metasurface for trapping hundreds of 100 nm polystyrene beads and multiplexed trapping of lipid vesicles.

Main Results:

• Successful parallel trapping of hundreds of 100 nm polystyrene beads over 10 minutes.
• Demonstrated multiplexed trapping of lipid vesicles using moderate optical intensity (<250 μW/μm²).
• The metasurface enables high-density nanoparticle trapping via near-field enhancement.

Conclusions:

• The developed resonant metasurface significantly advances large-scale multiplexed optical trapping capabilities.
• This technology opens new avenues for investigating the heterogeneity of biological systems at the nanoscale.
• Enables detailed studies of viruses, extracellular vesicles, and other nanoscale bioparticles.