Fig. 3

Experimental characterizations of OBH cavity. a Experimental setup of the microwave near-field scanning system. Inset: photograph of the fabricated sample. b Design aperture size distributions in OBH layered structures. c Comparison of simulated Q-factor in continuous and discrete OBH cavity with various azimuthal mode numbers. d Experimental normalized resonant spectra of OBH cavity and homogeneous cavity with mode number m = 3 and m = 4. The solid curves are Lorentz fittings. Measured WGM field pattern with mode number (e\(_1\)) m = 3 and (e\(_2\)) m = 4 . Simulated WGM field pattern with mode number (f\(_1\)) m = 3 and (f\(_2\)) m = 4. The white curves are the core and cladding material boundary of OBH cavity device