High power-efficiency terahertz quantum cascade laser

Li Yuan-Yuan, Liu Jun-Qi^†,, Liu Feng-Qi^‡,, Zhang Jin-Chuan, Zhai Shen-Qiang, Zhuo Ning, Wang Li-Jun, Liu Shu-Man, Wang Zhan-Guo

(a) L–I characteristics of 130-μm-wide, 2-mm-long Epi-down and Epi-up mounted devices at various temperatures in pulsed mode. The inset displays the threshold current density versus temperature for devices in both pulsed and CW operation. (b) L–I–V characteristics of the same devices in CW mode. The inset shows the lasing spectrum for the Epi-down mounted device at 10 K.