High-power, incoherent THz array sources are widely desired in some applications due to their low energy, unique terahertz fingerprint, and image. In this work, a dual ridge terahertz quantum cascade laser lasing at 3.1 THz is presented, and the device's performance is analyzed in detail. The maximum output power can reach 512 mW when the two ridges work simultaneously in continuous-wave mode, with a threshold current density of 281 A/cm2 at 15 K. While the peak power is approximately 704 mW in pulse-wave mode at 15 K, the lasing still could be observed approximately 7 mW at 125 K. The far-field pattern of the dual ridge THz QCL is detected by a THz camera; two light spots typically show a single-lobe Gaussian distribution. The experimental results provide a reference for realizing high-power THz quantum cascade lasers, and they will provide some guidance for the structural design of multiple ridges or laser arrays.
Keywords: quantum cascade lasers; quantum well; semiconductor lasers; terahertz.