Room temperature, single-mode 1.0 THz nonlinear quantum-cascade laser

We demonstrate a single-mode 1.0 THz non-linear quantum-cascade laser based on long wavelength dual-upper-state (DAU) active region. The DAU structure enables to obtain high power output in the long-wavelength mid-infrared range in which very high nonlinear susceptibility can be realized. As a result, we have improved their device performance on the low frequency side and have recently demonstrated multi-mode sub-terahertz nonlinear quantum cascade lasers at room temperature. In this paper, we fabricate a device with two-section buried distributed feedback grating configuration, and it operates in a single-mode at a frequency of 1.03 THz. Besides, a THz peak output power of 18 μW is obtained at room temperature.