Integrated photonics offers a promising alternative to conventional electronics by enabling high-bandwidth and energy-efficient data processing. Photonic Integrated Circuits (PICs) have the potential to replace electrical interconnects with photons as information carriers, but their further development requires compact and tunable optical components such as efficient light sources, high-speed frequency converters, and broadband photodetectors. While silicon photonics represents the current state-of-the-art platform for PICs, its weak nonlinear optical response, limited modulation speed, and restricted bandgap tunability constrain future miniaturization and device performance. Two-dimensional (2D) materials, including graphene and transition metal dichalcogenides (TMDs), provide a promising alternative due to their strong light–matter interaction, large nonlinear optical response, and tunable optoelectronic properties. This thesis investigates the optoelectronic and nonlinear optical properties of 2D materials and their heterostructures for advanced photonic applications. The work demonstrates ultrafast optical and optoelectronic modulation of second- and third-harmonic generation in monolayer MoS2 and graphene devices. In graphene, an 85% modulation depth of third-harmonic generation with sub-picosecond tunable response is achieved, while all-optical modulation in monolayer MoS2 reaches nearly 100% modulation depth. Furthermore, current-induced second-harmonic generation in graphene and charge-transfer-driven exciton–trion conversion in MoS2/graphene heterostructures are investigated. The influence of interlayer charge transfer on second-harmonic generation in bilayer MoS2/graphene devices is also analyzed. Finally, the effect of alloy composition in MoWSe2 on second-harmonic generation and two-photon photoluminescence is systematically studied. These results establish a foundation for future ultrafast photonic integrated circuits based on 2D materials.
Omid Ghaebi (Thu,) studied this question.