Terahertz beat frequency generation from two-mode lasing operation of coupled microdisk laser

Area of Science:

• Optics and Photonics
• Laser Physics
• Terahertz Science and Technology

Background:

• Microdisk lasers offer compact and tunable laser sources.
• Continuous-wave terahertz (THz) radiation generation is crucial for various applications.
• Photomixing is a common technique for THz wave generation.

Purpose of the Study:

• To propose a coupled microdisk laser for efficient THz radiation generation.
• To investigate the lasing dynamics and mode transitions under different pumping strengths.
• To explore the generation of tunable THz frequencies through light beating.

Main Methods:

• Utilized the Schrödinger-Bloch model to simulate laser behavior.
• Included the nonlinear effects of the active medium in the model.
• Analyzed resonant modes by solving the Schrödinger-Bloch model without nonlinear interactions.

Main Results:

• Observed both single-mode and two-mode lasing depending on pumping strength.
• Explained mode transitions by relating them to resonant modes.
• Demonstrated that two-mode lasing generates THz oscillations from the beating of nearly degenerate resonant modes with different symmetries.

Conclusions:

• A coupled microdisk laser can serve as a compact and tunable source for coherent continuous-wave THz radiation.
• The study provides insights into the underlying physics of mode selection and THz generation in such systems.
• This approach offers a promising pathway for developing advanced THz photonic devices.