Switching terahertz wave with grating-coupled Kretschmann configuration.

Area of Science:

• Optoelectronics
• Materials Science
• Terahertz Technology

Background:

• Terahertz (THz) wave devices require efficient switching mechanisms.
• Spoof surface plasmon polaritons (SSPPs) offer a route for THz wave manipulation.
• Liquid crystals provide tunable optical properties.

Purpose of the Study:

• To demonstrate a novel terahertz wave switch.
• To utilize the Kretschmann configuration for SSPP excitation.
• To achieve tunable THz intensity control using liquid crystals.

Main Methods:

• Fabrication of a device comprising a high-refractive-index prism, liquid crystal, and a periodically grooved metal grating.
• Excitation of SSPPs in the attenuated total reflection (ATR) regime.
• Modulation of liquid crystal refractive index via an external applied bias voltage.

Main Results:

• Successfully demonstrated a terahertz wave switch based on SSPP excitation.
• Achieved tunable control of ATR terahertz wave intensity by adjusting the applied voltage.
• Obtained a high extinction ratio of 31.48 dB for the terahertz switch.

Conclusions:

• The proposed terahertz switch exhibits good control ability and flexibility.
• The device is a potential candidate for future terahertz free-space systems.
• Liquid crystal tuning of SSPP excitation provides an effective switching mechanism.