Room temperature continuous wave operation of quantum cascade laser at λ ~ 9.4 μm * * Project supported by the National Key Research And Development Program (No. 2016YFB0402303), the National Natural Science Foundation of China (Nos. 61435014, 61627822, 61574136, 61774146, 61674144, 61404131), the Key Projects of Chinese Academy of Sciences (Nos. ZDRW-XH-2016-4, QYZDJ-SSW-JSC027), and the Beijing Natural Science Foundation (No.

Abstract

Continuous wave (CW) operation of long wave infrared (LWIR) quantum cascade lasers (QCLs) is achieved up to a temperature of 303 K. For room temperature CW operation, the wafer with 35 stages was processed into buried heterostructure lasers. For a 2-mm-long and 10-μm-wide laser with high-reflectivity (HR) coating on the rear facet, CW output power of 45 mW at 283 K and 9 mW at 303 K is obtained. The lasing wavelength is around 9.4 μm locating in the LWIR spectrum range.