InAs quantum-dot laser utilizing GaAs photonic-crystal line-defect waveguide.

Area of Science:

• Photonics
• Materials Science
• Quantum Optics

Background:

• Photonic crystal slabs offer unique light manipulation properties.
• Indium arsenide (InAs) quantum dots are promising gain media for semiconductor lasers.
• Integrated photonic devices require compact and efficient laser sources.

Purpose of the Study:

• To demonstrate laser action from InAs quantum dots in a photonic crystal waveguide.
• To investigate the mechanism behind lasing in the absence of a traditional optical cavity.
• To explore the potential of this system for ultrafast photonic integrated circuits.

Main Methods:

• Optical pumping of InAs quantum dots embedded in a line-defect waveguide within an air-bridge GaAs-photonic-crystal slab.
• Analysis of transmittance spectrum and comparison with calculated W3 defect-mode band dispersion.
• Investigation of lasing wavelength at the photonic band edge.

Main Results:

• Observed laser action from optically-pumped InAs quantum dots.
• Lasing occurred without a conventional optical cavity (e.g., Fabry-Perot mirrors).
• Lasing wavelength identified at the band edge, indicating a distributed feedback mechanism.

Conclusions:

• Distributed feedback at the band edge, coupled with near-zero group velocity, enables lasing in this structure.
• This compact laser design is suitable for future ultrafast planar photonic integrated circuits.
• The findings pave the way for novel laser architectures in integrated photonics.