Photonically driven pseudo-continuous and broadband THz phase shifting using spatially resolved photoconductivity...

Area of Science:

• Terahertz (THz) technology
• Optoelectronics
• Materials science

Background:

• Terahertz (THz) phase shifters are crucial for advanced wireless communication and sensing.
• Current THz phase shifting technologies face limitations in performance, bandwidth, and design flexibility.
• The need for efficient, broadband, and reconfigurable THz devices is increasing for next-generation applications.

Purpose of the Study:

• To develop and demonstrate a novel, high-performance, and broadband THz phase shifting approach.
• To investigate the efficacy of spatially-resolved photoconductivity modulation (SRPM) for continuous phase tuning.
• To design and simulate a photonically-driven THz phase shifter for WR-5.1 waveguide applications.

Main Methods:

• Utilized a hybrid Au-Ge mesa-array (AGMA) structure and an indium tin oxide (ITO) layer for local photoconductivity modulation.
• Employed computer-generated light patterns from a micro-LED array for SRPM, eliminating the need for biasing circuitry.
• Designed, modeled, and simulated a WR-5.1 waveguide-based THz phase shifting device with a 12x6 unit cell mesa-array.

Main Results:

• Achieved pseudo-continuous and broadband THz phase shifting across the entire WR-5.1 band (140-220 GHz).
• Demonstrated a phase tuning range of 0° to -180° at 180 GHz with minimal reflection loss (<1 dB).
• Showcased fine phase tuning steps as small as ~0.05° using specific light pattern combinations.

Conclusions:

• The SRPM approach offers a novel and unique method for high-performance THz phase shifting.
• The proposed technology provides superior design flexibility and frequency scalability compared to existing methods due to the absence of biasing wires.
• This technology is highly promising for developing large-scale THz phased-arrays and reconfigurable devices for 6G and beyond wireless communications.