Self-consistent simulations of intracavity terahertz comb difference frequency generation by mid-infrared quantum cascade lasers

Portable terahertz (THz) frequency comb sources are highly desired for applications in rotational molecular spectroscopy and sensing. To date, direct THz quantum cascade laser (QCL) generation is not achievable at room temperature. However, based on intracavity difference (DFG) mid-infrared (mid-IR) QCLs a promising alternative. Here, we present numerical study of DFG-QCL formation mid-IR self-consistent multi-domain simulation approach. The dynamical simulations performed using our open-source software tool mbsolve, which provides flexible efficient codebase solving the generalized full-wave Maxwell–Bloch equations. DFG active region dual-wavelength QCL considered radiation. mixing process and, thus, require high second-order intersubband nonlinear susceptibility can be obtained by targeted engineering. associated effects included Hamiltonian All necessary input parameters description system determined self-consistently in-house ensemble Monte Carlo stationary carrier transport simulations. Notably, such solver that does employ common rotating wave approximation, as broadband optical field extending from to investigated. Our modeling approach results two setups validated against experimental data, showing reasonable agreement. Furthermore, obtain locked modulated state regimes.