All-optical controlled ternary encoding polarization THz modulator-based on a vanadium dioxide-metal bilayer...

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Terahertz (THz) polarization modulators are crucial for THz wireless communication.
• Current modulators face challenges in achieving high efficiency and multifunctionality with optical excitation.

Purpose of the Study:

• To propose a novel vanadium dioxide (VO2)-metal hybrid bilayer metasurface for multifunctional polarization modulation.
• To demonstrate independent control over polarization states using optical pump excitations.

Main Methods:

• Fabrication of a VO2-metal hybrid bilayer metasurface.
• Utilizing two independent optical pump excitations to manipulate the insulator-to-metal transition of VO2 bars.
• Characterizing the polarization switching capabilities of the metadevice.
• Developing an equivalent circuit model to explain the resonance mechanism.

Main Results:

• The proposed metadevice can achieve dynamic switching between left-handed circular polarization, right-handed circular polarization, and linear polarization states.
• A ternary encoding scheme for output polarization states was successfully proposed.
• An equivalent circuit model validated the physical mechanism of resonances.

Conclusions:

• The study presents a novel method for designing multifunctional metadevices.
• The developed technology significantly advances polarization modulation for terahertz communications.