Distributed feedback terahertz quantum cascade lasers with complex-coupled metallic gratings

The singlemode operation of a distributed feedback terahertz quantum cascade laser with complex-coupled metallic relief gratings emitting at 3.09 THz (λ=97.07 µm) is reported. The side-mode suppression ratio is about 20 dB at all operating temperatures. The highest working temperature of up to 88 K is obtained, with the optical power of 10 mW at 10 K and 1 mW at 88 K.