Liquid crystal integrated metalens with dynamic focusing property

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Metalenses are advancing terahertz (THz) devices, with tunable capabilities being a key research area.
• Integrating liquid crystals (LCs) with dielectric metasurfaces offers a promising route for dynamic control.

Purpose of the Study:

• To propose and demonstrate a strategy for dynamic focal spot manipulation using integrated dielectric metasurfaces and liquid crystals.
• To achieve polarization-multiplexed focusing and tunable terahertz functionalities.

Main Methods:

• Designing silicon pillar meta-units to create distinct phase profiles for orthogonal polarizations.
• Integrating liquid crystals to enable electrically controlled orientation changes.
• Fabricating and testing two distinct metalenses for polarization conversion and beam deflection.

Main Results:

• Demonstrated dynamic focal spot manipulation (lateral/axial alteration) via electrically controlled LC orientations.
• Developed a metalens acting as a polarization converter with bias-controlled focal length switching.
• Implemented a second metalens utilizing an LC polarization grating for spin-selective beam deflection.

Conclusions:

• The proposed integration strategy provides a promising method for active terahertz elements.
• These tunable metalenses show potential for widespread application in terahertz sensing, imaging, and communication.