Low-threshold lasing in photonic-crystal heterostructures.

Area of Science:

• Photonics
• Materials Science
• Condensed Matter Physics

Background:

• Photonic crystals (PhCs) offer unique light manipulation properties.
• Achieving low lasing thresholds in PhC-based devices is crucial for on-chip integration.
• Heterostructure cavities can enhance light-matter interactions.

Purpose of the Study:

• To investigate a novel photonic crystal heterostructure cavity for laser applications.
• To determine the impact of the heterostructure design on lasing threshold.
• To explore the potential for ultra-low threshold on-chip lasers.

Main Methods:

• Fabrication of a three-dimensional (3D) PhC heterostructure cavity with a gain medium.
• Utilizing the Korringa-Kohn-Rostoker (KKR) method for theoretical analysis.
• Analyzing the overlap between defect cavity modes and PhC dispersion characteristics.

Main Results:

• Observed a two-order-of-magnitude decrease in lasing threshold compared to a standalone 3D PhC.
• Attributed threshold reduction to the overlap of defect cavity mode with reduced group velocity regions.
• Demonstrated enhanced distributed feedback from the ordered multilayer structure.

Conclusions:

• The proposed PhC heterostructure cavity significantly lowers lasing thresholds.
• This design is effective for enhancing light-matter interaction and feedback.
• The findings pave the way for developing compact, ultra-low threshold on-chip lasers.