부산대학교 도서관

We report mass-producible room-temperature electrically-pumped THz sources based on intra-cavity difference-frequency generation in mid-infrared InGaAs/AlInAs/InP quantum cascade lasers. Devices are grown by a commercial foundry using metal organic vapor phase epitaxy. A dual-stack active region possessing giant optical nonlinearity for 3.5 THz generation and a non-collinear Cherenkov waveguide THz outcoupling scheme is employed. Fabry–Pérot devices provided broad emission in the 3–4 THz range with a peak power of 5 $\mu{\rm W}$. Single color THz sources were processed using surface distributed feedback gratings to produce narrowband $({ emission at 3.5 THz with nearly 40 $\mu{\rm W}$ of peak power and a mid-infrared-to-THz conversion efficiency of 0.36 ${\rm mW}/{\rm W}^{{2}}$. To better understand the dynamics of the DFG process, time gated spectral measurements of the mid-infrared pumps were performed and simultaneous lasing over the duration of the applied bias pulse was observed, thereby resulting in efficient difference frequency generation.