Simulation of terahertz whispering gallery mode resonator

In this paper, we used FDTD optical simulation software to simulate terahertz whispering gallery mode resonant cavities with cylindrical, circular ring, sphere, and hollow sphere structures. We used fiber coupling method and set the diameter of the fiber to 200um. Simulate resonant cavities with a radius of 5mm to 10mm in the range of 0.325-0.5THz. The resonant cavity uses quartz material and uses 2D simulation to save simulation time. We observed the distribution of mode spectral lines and electric field intensity, and characterized five indicator parameters of the terahertz whispering gallery mode resonant cavity after resonance phenomenon: resonance wavelength, free spectrum range, full width at half maximum, quality factor, and mode volume. The results indicate that terahertz resonant cavities exhibit good performance in specific frequency bands.