Controllable double-helical microstructures by photonic orbital angular momentum for chiroptical response

Area of Science:

• Nanophotonics
• Metamaterials Science
• Optical Engineering

Background:

• Three-dimensional helical microstructures are prevalent in nature.
• These structures hold potential as chiral metamaterials for advanced nanophotonics applications.
• Existing fabrication methods may lack flexibility or efficiency.

Purpose of the Study:

• To develop a flexible and efficient method for fabricating double-helical microstructures.
• To utilize the chirality of incident optical vortices for microstructuring.
• To demonstrate the tunable nature and reversible read-out of the fabricated structures' chirality.

Main Methods:

• Fabrication of double-helical microstructures via single exposure using interfering coaxial optical vortices.
• Numerical simulations to confirm the generation of a helical optical field.
• Tailoring microstructure diameters by adjusting the topological charges of optical vortices.
• Demonstrating reversible chirality detection using optical vortices.

Main Results:

• Successful fabrication of double-helical microstructures through a novel single-exposure method.
• Confirmation of helical optical field generation via numerical simulation.
• Demonstrated control over microstructure diameter by varying topological charges.
• Exhibited a strong chiroptical response with reversible read-out capability.

Conclusions:

• The reported method offers a fast and efficient strategy for producing helical microstructures.
• The fabricated double-helical microstructures exhibit tunable dimensions and strong chiroptical properties.
• This technique provides a promising platform for developing advanced chiral metamaterials for nanophotonics.