High-power and high-beam-quality photonic-crystal surface-emitting lasers: a tutorial

Realization of single-mode, high-power and high-beam-quality (namely, high-brightness) semiconductor lasers, which can rival or even replace bulky lasers such as gas, solid, and fiber lasers, is one of the ultimate goals of laser physics and photonics. The demand for such ultimate single-mode high-brightness semiconductor lasers is increasing for a wide variety of emerging applications including next-generation remote sensing for smart mobility and high-precision laser processing for smart manufacturing. Photonic-crystal surface-emitting lasers (PCSELs) show promise to meet these demands, based on their broad-area coherent two-dimensional (2D) resonance at a singularity (Γ) point of their 2D photonic band structure. In this tutorial paper, the lasing principle, theoretical analysis, and experimental demonstration of PCSELs are described. Recent progress in PCSEL development, including the formulation of a design guideline for realizing 100-W-to-kW-class single-mode operation, the experimental demonstration of a brightness of 1 GW cm –2 sr –1 , and an extension of the lasing wavelengths to telecommunication and mid-infrared wavelengths are also covered.