High Output Power (>20 W) and High Quantum Efficiency in a Photopumped ZnSe/ZnSSe Blue Laser Operating at Room Temperature

Abstract
High output power of 24 W was observed from a photopumped ZnSe/ZnSSe blue laser operating at room temperature. A differential quantum efficiency greater than 25% was estimated in the lasing region of the photopumped wafer. The improved lasing property is attributed mainly to the improved waveguiding structure verified from the far-field measurement. The other is the introduction of a ZnSe/ZnSSe superlattice buffer which improved the crystalline property of the active layer grown above. The lowest threshold power was 50∼70 kW/cm2 for a cavity length of 220 µm under pulsed operation.