Terahertz isolator based on nonreciprocal magneto-metasurface

Area of Science:

• Metamaterials and Nanophotonics
• Terahertz (THz) Science and Technology
• Magneto-optics

Background:

• Terahertz (THz) isolators are essential components for preventing signal reflection and ensuring unidirectional signal propagation in THz systems.
• Existing THz isolators often suffer from bulky structures, high losses, or narrow bandwidths, limiting their practical applications.
• Metasurfaces offer a promising platform for miniaturized and efficient optical devices due to their subwavelength structure and tailored electromagnetic responses.

Purpose of the Study:

• To propose and investigate a novel magneto-metasurface capable of achieving nonreciprocal terahertz transmission.
• To identify and analyze the key conditions required for enabling nonreciprocal THz transmission in metasurfaces.
• To explore the performance characteristics and tunability of the proposed THz isolator.

Main Methods:

• Theoretical analysis of magneto-optical effects and asymmetry in metasurface structures.
• Numerical simulations to model terahertz wave propagation and device performance.
• Investigation of the influence of external magnetic field and temperature on device isolation and bandwidth.

Main Results:

• Demonstrated that magneto-optical response and system asymmetry are crucial for nonreciprocal THz transmission.
• Observed magnetoplasmon mode splitting and nonreciprocal resonance enhancement in the asymmetric magneto-metasurface.
• Achieved a maximum isolation of 43 dB and a 10 dB operating bandwidth of 20 GHz with an insertion loss below 1.79 dB.

Conclusions:

• The proposed magneto-metasurface effectively functions as a high-performance THz isolator.
• The device exhibits excellent isolation, low loss, and tunable characteristics, making it suitable for various THz applications.
• This work provides a pathway for designing advanced, compact THz components.