Third-harmonic generation in one-dimensional photonic crystal with graphene-based defect

Third-harmonic generation may be dramatically enhanced in monolayer graphene by inserting it in a properly designed structure. In addition, placing graphene within the defect layer of an asymmetric, one-dimensional photonic crystal triggers nearly 100% narrowband absorption. We demonstrate that the improved field localization within the defect state enhances third-harmonic generation by nearly five orders of magnitude compared with bare monolayer graphene. Saturation of the third-order susceptibility plays a role at both fundamental and third-harmonic frequencies. We discuss the benefits of including graphene within the structure for both signals.