Optically pumped lasing with a Q-factor exceeding 6000 from wet-etched GaN micro-pyramids

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Gallium Nitride (GaN) is a crucial semiconductor for optoelectronic applications.
• Microcavities are essential for enhancing light-matter interactions and achieving lasing.
• Achieving room-temperature lasing in GaN microstructures is a significant challenge.

Purpose of the Study:

• To demonstrate room-temperature optically pumped lasing from a single GaN pyramid microcavity.
• To investigate the optical resonance properties of these microcavities.
• To explore the potential of GaN pyramid microcavities for photonic applications.

Main Methods:

• Fabrication of GaN pyramid microcavities using a selective wet-etching technique.
• Characterization of lasing modes using optical pumping at room temperature.
• Analysis of lasing properties including threshold, linewidth, and quality factor.
• Three-dimensional finite-difference time-domain (FDTD) simulations for optical resonance investigation.

Main Results:

• Observation of room-temperature optically pumped lasing modes at 367.2 nm.
• Achieved a low lasing threshold of 0.4-0.5 MW/cm².
• Measured a narrow linewidth of 0.054 nm, indicating a quality factor >6000.
• Demonstrated the effectiveness of the wet-etching approach and Ag reflectors for light confinement.

Conclusions:

• The developed GaN pyramid microcavity exhibits excellent lasing performance at room temperature.
• The fabrication method successfully reduces defects and enhances optical confinement.
• These results highlight the potential of GaN pyramid microcavities for future optoelectronic and photonic integrated circuits.