On-chip single-mode high-Q terahertz whispering gallery mode resonator

The chip-scale terahertz (THz) devices and systems are helpful to enable actual applications in THz communication and sensing. Here, we demonstrate an on-chip THz whispering gallery mode resonator (WGMR) delivering a high-quality (Q) factor TE single mode, fabricated on a high-resistivity float zone silicon wafer by complementary metal–oxide–semiconductor compatible technology. For a TE mode in a WGMR, it is the first time to achieve a Q factor of 1210 at 0.4925 THz with 28 dB extinction ratio, to the best of our knowledge. With this excellent WGMR, we have demonstrated a stable and highly sensitive sensor for particle distance estimation. Our investigation provides an effective approach to fabricate high-performance integrated THz-WGMRs for chip-scale systems.