Demonstration of Hybrid High-Q Hexagonal Boron Nitride Microresonators

Abstract

Hexagonal boron nitride (hBN) is a wide bandgap van der Waals material that is emerging as a powerful platform for quantum optics and nanophotonics. In this work, we demonstrate whispering gallery mode silica microresonators hybridized with thin layers of hBN that exhibit high intrinsic optical quality factor >7 x 10(5) and a linear absorption coefficient of 9.5 cm(-1). Measurements of the effect of hBN thickness on optical Q and comparison with a theoretical model allows the linear optical absorption coefficient of the hBN films to be estimated. These high-Q devices will be useful for applications in quantum and nonlinear optics, and their hybridized geometry provides a sensitive platform for evaluating losses in hBN and other 2D materials.