Robust single-mode laser via merging bound state in the continuum.

Area of Science:

• Photonics
• Laser Physics
• Materials Science

Background:

• Bound states in the continuum (BICs) offer strong light confinement for photonic applications.
• Existing BIC lasers face challenges with mode competition and fabrication, limiting performance and size.
• High-performance, compact BIC lasers are crucial for advanced photonic devices.

Purpose of the Study:

• To demonstrate a robust, single-mode laser utilizing the merging BIC concept.
• To achieve stable lasing behavior under high-power excitation.
• To realize an ultra-compact photonic crystal laser through BIC mode and edge engineering.

Main Methods:

• Leveraging the "merging BIC" concept in momentum space for stable lasing.
• Employing edge engineering to combine BIC modes in a compact structure.
• Fabricating a 5×5 periodic array photonic crystal with a sub-15 μm² patterned area.

Main Results:

• Demonstrated stable lasing behavior up to 80 times the threshold power.
• Showcased exceptional mode stability under high-power excitation.
• Realized an ultra-compact photonic crystal laser with a minimal footprint.

Conclusions:

• The merging BIC concept enables robust, single-mode lasing with enhanced stability.
• Edge engineering combined with BIC modes leads to ultra-compact laser designs.
• This work presents a viable pathway for high-performance, miniaturized lasers in photonic applications.