Room temperature continuous-wave operation of a dual-wavelength quantum cascade laser

We report on the design and fabrication of a dual-wavelength switchable quantum cascade laser (QCL) by optimizing homogeneous active region combining superposed distributed feedback gratings. Coaxial, single-mode emissions at two different wavelengths were achieved only through adjusting bias voltage. Room temperature continuous-wave operation with output powers above 30 mW 75 was realized for emission 7.61 µm 7.06 µm, respectively. The simplified process easy wavelength control our designed QCL make it very attractive developing miniature multi-species gas sensing systems.