Single mode lasing and spectral narrowing in photonic crystal line-defect cavities via spatially selected Bloch modes

TL;DR

This paper proposes a theoretical method to achieve single-mode lasing in photonic crystal line-defect cavities by spatially selecting Bloch modes through optical interference, enhancing laser performance and spectral purity.

Contribution

The study introduces a novel scheme for single-mode lasing in PhC microcavities by spatially pumping specific Bloch modes, improving mode control and laser quality.

Findings

Achieved side mode suppression ratio exceeding 30 dB.

Enhanced linewidth and noise characteristics through optical interference.

Demonstrated the viability of Bloch mode selection for PhC laser manipulation.

Abstract

The demand for high-efficiency and miniaturized on-chip light sources drives continuous innovation in photonic crystal (PhC) microcavity lasers. The presence of slow-light effects in PhC microcavities leads to the mode competition between Bloch modes resulting in multi-mode lasing, which obstructs the dense integration of PhC lasers. Here, we theoretically verify a technical scheme for the single-mode lasing of PhC line-defect-cavity lasers by spatially pumping a certain Bloch mode via optical interference.We demonstrate the capability to select a specific longitudinal mode to lase with a side mode suppression ratio (SMSR) exceeding 30 dB. The interaction between optical interference fringes and the vacuum electromagnetic field inside the PhC cavity improves the linewidth and noise characteristics of lasers. This scheme of Bloch mode selection provides a novel and viable tool for the manipulation of PhC microcavity lasers.