Characteristics of GaN-based photonic crystal surface-emitting lasers

Characteristics of GaN-based photonic crystal surface-emitting lasers (PCSELs) were investigated and analyzed. We demonstrated two different lattice constant of the GaN-based PCSEL. One with lattice constant of 290nm emits a blue wavelength at 401.8 nm with a linewidth of 1.6 Å and shows a threshold energy density about 2.7 mJ/cm² under the optical pumping at room temperature. The other with lattice constant of 234nm observed a wavelength at 423.8nm with a linewidth of 1.1 Å and energy density about 3.5 mJ/cm ². The laser emission covers whole circularly 2D PC patterns (50 μm in diameter) with a small divergence angle. The lasing wavelength emitted from 2D PC lasers with different lattice constants occurs at the calculated band-edges provided by the PC patterns. The characteristics of large area, small divergence angle, and single mode emission from the GaN-based 2D surface-emitting PC lasers should be promising in high power blue-violet emitter applications. The lasing wavelength emitted from PCSELs 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. Furthermore, the PCSEL also shows a spontaneous emission coupling efficiency β of about 5×10 ^-3 and a characteristic temperature of 148K.