Development of active silicon nitride nanophotonic platform with emerging materials

Abstract

The field of integrated photonics has grown rapidly in the past few decades, with numerous applications in data communication, quantum technology and biomedical sensing. Among various emerging platforms for photonic integration, silicon nitride (SiN) has recently become an excellent candidate thanks to its low optical loss over a broad transparent window, together with the CMOS compatibility. However, most SiN photonic components demonstrated so far are passive devices for guiding photons. Further development of active components, including photon sources and nonlinear photonics components, is required for both classical and quantum applications. One promising direction is to heterogeneously integrate novel optoelectronics materials onto the SiN platform. In this thesis, I present my work on the hybrid SiN photonics platform with two emerging materials: solution-processed colloidal quantum dots (QDs) and transition metal dichalcogenides (TMD) monolayer. I focus on the fundamental study of light-matter interaction between these quantum-confined materials with the integrated SiN photonic cavities. For colloidal QDs, I demonstrate deterministic positioning of these emitters on SiN photonic crystal nanobeam cavity and observe the Purcell enhancement and saturable photoluminescence. For monolayer TMD, I demonstrate the strong coupling between the two-dimensional excitons with a SiN metasurface. Apart from the light-matter interaction, I also explore tunable SiN integrated cavities and demonstrate the large thermal tuning of a polymer embedded SiN nanobeam cavity, together with the active tuning of a heterogenous photonic molecule. The work presented paves the way for future development of cavity-enhanced light sources, ultra-low-power optical switch, and quantum photonic simulators on the SiN platform.