Terahertz transmissive half-wave metasurface with enhanced bandwidth

Area of Science:

• Terahertz (THz) photonics
• Metasurface optics
• Chiral structure analysis

Background:

• Polarization conversion is crucial for chiral studies and communication systems.
• Conventional wave plates face limitations in material availability, bandwidth, and efficiency, especially at terahertz frequencies.

Purpose of the Study:

• To develop a broadband, high-efficiency transmissive half-wave plate for terahertz applications.
• To overcome the limitations of traditional wave plates using metasurface technology.

Main Methods:

• Designed a Huygens' metasurface half-wave plate.
• Utilized a broadband semi-analytical approach to determine optimal frequency-independent circuit parameters.
• Simulated and fabricated the metasurface for experimental validation.

Main Results:

• Simulations predicted a 15-dB extinction ratio from 219 GHz to 334 GHz (41.6% fractional bandwidth).
• Fabricated metasurface achieved a 15-dB extinction ratio from 220 GHz to 303 GHz.
• Demonstrated cross-polarization transmission efficiency exceeding 76.7% for both linear and circular polarizations.

Conclusions:

• The designed half-wave metasurface offers enhanced bandwidth and efficiency for terahertz polarization conversion.
• This metasurface provides a viable solution for compact terahertz systems, enabling diverse applications.
• The frequency-independent design approach facilitates integration and scalability.