Room Temperature Lasing of Multi-Stage Quantum-Cascade Lasers at 8 μm Wavelength

Resumo

Room-temperature lasing at a wavelength of 8 μm in multistage quantum-cascade lasers pumped by current pulses is demonstrated. A quantum-cascade laser heterostructure based on the In_0.53Ga_0.47As/A_l0.48In_0.52As alloy heteropair, matched to an InP substrate, is grown by molecular-beam epitaxy and consists of 50 identical cascades placed in a waveguide with air as the top cladding. A threshold current density of ~5.1 kA/cm² at a temperature of 300 K is obtained in ridge lasers with a cavity length of 1.4 mm and a ridge width of 24 μm.