Reducing the reflection error of PML absorbing boundary conditions within a generalized Maxwell-Bloch framework

We demonstrate a full-wave numerical Maxwell-Bloch simulation tool including perfectly matched layer (PML) absorbing boundary conditions. To avoid detrimental reflection errors at the boundary of the simulation domain, an adapted PML model is introduced, which takes into account impedance mismatch effects arising from the internal quantum system. For the numerical validation of the modified PML model the simulation tool is applied to the active gain medium of a terahertz quantum cascade laser (QCL) structure. Improved absorbing characteristics for the truncation of active gain media in our Maxwell-Bloch simulation approach are obtained.