On-chip terahertz isolator with ultrahigh isolation ratios

Area of Science:

• Photonics and Optics
• Materials Science
• Electromagnetism

Background:

• Terahertz (THz) isolators are crucial nonreciprocal devices for manipulating THz wave propagation in complex systems.
• Breaking Lorentz reciprocity is essential for device functionality, enabling directional control of electromagnetic signals.
• Existing THz isolators often face challenges in integration, tunability, and performance.

Purpose of the Study:

• To report an integrated terahertz isolator based on a magneto-optical nonreciprocal resonator.
• To demonstrate ultrahigh isolation and low insertion loss for efficient THz signal manipulation.
• To achieve tunable operation across a specific frequency range for versatile applications.

Main Methods:

• Fabrication of an integrated terahertz isolator utilizing a nonreciprocal resonator.
• Optimization of the resonator's magneto-optical properties and loss characteristics.
• Experimental characterization of the device's isolation, insertion loss, and frequency tunability.

Main Results:

• Experimental observation of unidirectional terahertz wave propagation.
• Achieved an ultrahigh isolation ratio of up to 52 dB.
• Measured an insertion loss of approximately 7.5 dB at ~0.47 THz.
• Demonstrated thermal tuning for operation across the 0.405–0.495 THz range.

Conclusions:

• The developed on-chip terahertz isolator offers superior nonreciprocal performance.
• The device's tunable nature and high isolation pave the way for practical THz applications.
• This work provides a promising platform for future integrated terahertz nonreciprocal devices.