Large-Scale Robust Quantum Dot Microdisk Lasers with Controlled Cavity Modes

We report the facile on-chip fabrication of CdSe/Cd_1-xZn_xSe_1-yS_y quantum dots microdisk lasers and their large-area arrays via a pattern-assisted layer-by-layer assembly process. This approach combines the versatility of colloidal semiconducting nanoparticles (bright emission, solubility, and high stability) with the spatial precision of optical lithography to create robust large-area optical lasing arrays (up to a few thousand disks). Specifically, microdisk lasers with high quality factors (within 1000-2000) were fabricated with predefined size and shape (as controlled by master templates) with high consistency and throughput, essentially providing a new approach to fabricate difficult-to-control on-chip optical cavities in a low-cost and effective manner. Notably, the number of longitudinal cavity modes in the microdisk laser can be precisely controlled by varying the microdisks’ diameter, allowing for either near-single mode or multimode operation while preserving high quality factors. As such, these quantum dot microdisk laser arrays are promising candidates for advancing the development of large-area, low-cost on-chip photonic structures with controlled lasing modes.