GaN-based 2-D photonic crystal (PC) surface-emitting lasers (PCSELs) with AlN/GaN distributed Bragg reflectors are fabricated and investigated. A clear threshold characteristic under the optical pumping at room temperature is observed at about 2.7 mJ/cm2 with PC lattice constant of 234 nm. Above the threshold, only one dominant peak appears at 401.8 nm with a linewidth of 0.16 nm. The laser emission covers whole circular 2-D PC patterns of 50 μ m in diameter with a small divergence angle. The lasing wavelength emitted from 2-D PC lasers with different lattice constants occurs at the calculated band edges, showing different polarization angles due to the light diffracted in specific directions, corresponding exactly to Γ-K-, and M-directions in the K space. The PCSEL also shows a spontaneous emission coupling factor β of 5× 10-3 and a characteristic temperature of 148 K. Furthermore, the coupled-wave model in 2-D hexagonal lattice is applied to distinguish the discrepancy in threshold power and the corresponding coupling coefficient. The results show that the lasing actions within Γ, K, and M modes have a substantial relation between the threshold energy density and the coupling coefficient.
|Number of pages||7|
|Journal||IEEE Journal on Selected Topics in Quantum Electronics|
|State||Published - 1 May 2009|
- Hexagonal lattice
- Photonic crystal (PC)
- Surface-emitting lasers