Voltage-controlled terahertz metasurface modulator for gallium nitride films

Area of Science:

• Optoelectronics
• Metamaterials
• Terahertz (THz) Technology

Background:

• Dynamic control of terahertz (THz) metasurfaces is crucial for advanced THz devices.
• Semiconductor integration with metasurfaces allows for tunable functionalities via external excitation.
• Gallium Nitride (GaN) offers excellent optoelectronic properties like long diffusion length and tunable bandgap.

Purpose of the Study:

• To develop a voltage-controlled modulator for THz waves using Gallium Nitride (GaN) metasurfaces.
• To leverage the tunable conductivity of GaN under electrical excitation for precise metasurface tuning.

Main Methods:

• Integration of Gallium Nitride (GaN) with metasurfaces.
• Application of electrical bias voltage to modulate GaN conductivity.
• Characterization of THz wave modulation depth and phase shift.

Main Results:

• Achieved a modulation depth of up to 42.44% under bias voltage.
• Demonstrated a maximum phase shift of 230.5° at 0.66 THz.
• Exhibited highly sensitive switching control of metasurface resonance in the THz range.

Conclusions:

• The developed GaN-based THz modulator offers significant phase modulation capabilities, surpassing conventional devices.
• This voltage-controlled device shows vast potential for next-generation micro- and nanophotonic devices.
• The study highlights the effectiveness of electrical excitation for dynamic THz metasurface control.