Unraveling the Nature of Lasing Emission from Hybrid Silicon Nitride and Colloidal Nanocrystal Low Refractive Index Photonic Crystals

Silicon nitride is used for its low optical loss and high thermal stability, making it a suitable platform for visible-light applications for integrated photonic devices. However, its application has been limited due to inefficient light emission, a problem addressed by integrating various types of light emitters onto the platform. In particular, the integration of solution-processable colloidal nanocrystals (NCs) as optical gain materials onto the silicon nitride platform is a promising route, but requires a more solid theoretical footing. By leveraging 2D surface emitting photonic crystal structures combined with NCs, we effectively confine and manipulate light to achieve lasing from green to red. These types of cavities, although often used in combination with solution-processible semiconductors, has not yet been thoroughly investigated. To do this, we start by modeling the light-matter interactions of the low index contrast NC/nitride platform, and then validate these by extensive experimental Fourier imaging techniques revealing the full photonic band structure and showing clear mode congestion. These comprehensive studies confirm the potential of hybrid NC-based structures for fully integrated on-chip laser applications and indicate routes for further improvement.