Dual functional device featuring absorption and polarization conversion based on temperature controlled metasurface...

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz (THz) Technology
• Condensed Matter Physics

Background:

• Terahertz (THz) devices often require complex structures for multifunctional applications.
• Achieving tunable absorption and polarization conversion simultaneously presents a significant challenge.
• Existing multifunctional metasurfaces can be bulky and difficult to fabricate.

Purpose of the Study:

• To develop a dual-functional terahertz metasurface device.
• To enable switchable operation between polarization conversion and absorption.
• To leverage the temperature-dependent properties of vanadium dioxide (VO₂) for tunability.

Main Methods:

• Design and simulation of a metasurface unit cell with metallic and VO₂ elements.
• Utilizing the metal-insulator phase transition of VO₂ (at 68°C) for switching functionalities.
• Characterizing the device performance across different temperature regimes.

Main Results:

• The metasurface acts as a linear-to-linear cross-polarization converter (LTLPC) from 0.66-1.7 THz at room temperature (insulating VO₂).
• The device functions as an absorber (>80% absorptivity) from 0.34-1.96 THz above 351 K (metallic VO₂).
• Achieved broadband operation with fractional bandwidths of 88% for LTLPC and 140% for absorption.

Conclusions:

• The proposed simplified metasurface offers switchable dual functionality (polarization conversion and absorption) in the terahertz range.
• The device demonstrates advantages in terms of geometry, fabrication, and enhanced broadband performance compared to existing multifunctional structures.
• This work presents a practical and scalable platform for reconfigurable terahertz components with potential applications in measurement and communication systems.