  In this paper we explore the capabilities of MoS2 and WS2 2D monolayers to
produce radiation in the terahertz range by generation of high-order harmonics.
This phenomenon, which is a result of the non-linear response of the electronic
carrier population to the applied electric field, is studied by using a
particle ensemble stochastic simulation approach based on the Monte Carlo
method. The power of the produced harmonic signals is studied against the
electric field amplitude, the external temperature, and the frequency of the
excitation. Additionally, the stochastic nature of the simulation tool enables
to discern the purely discrete harmonic signal from the background spectral
noise that comes from the intrinsic carrier velocity fluctuations in the
diffusive regime, permitting to set bandwidth thresholds for harmonic
extraction. It was found that both TMDs showed similar thresholds bandwidths
when compared to III-V semiconductor at low temperatures, while WS2 would be by
far a better choice, over MoS2, for exploitation of the 7th and 9th harmonic
generation.
