Dielectric bubble whispering gallery mode terahertz resonator

Micro ring and micro bubble resonators are of enormous importance in the optical regime [1], [2], however little work has yet been done in the terahertz (THz) realm [3]. In this work we present simulations and measurements of whispering gallery modes (WGMs) in a dielectric bubble resonator at THz frequencies. The resonators are numerically analyzed with both finite element method as well as Mie scattering theory. The experiments are performed with a continuous wave THz spectrometer. At critical coupling a very high Q-factor of more than 400 at 0.465 THz is experimentally observed. The measured Finesse of the THz bubble resonator is ~ 9. The enormous potential of bubble WGM THz resonators for sensing applications are discussed.