We report what is to our knowledge the first observation of a subpicosecond terahertz (THz) pulse propagating as a superposition of the whispering-gallery modes (WGMs) of a dielectric cylinder. The WGM THz pulses are coupled into and out of a 5-mm-diameter silicon cylinder via a 100-μm -thick, single-mode silicon slab waveguide. We observed two round-trip cylindrical cavity pulses from this coupling structure, which cover a continuous frequency range from 0.4 to 1.8 THz. The coupled-mode equations are used to analyze this system and give reasonably good agreement with the experiment in both the frequency and the time domains.
© 2002 Optical Society of America
Jiangquan Zhang and D. Grischkowsky, "Whispering-gallery mode terahertz pulses," Opt. Lett. 27, 661-663 (2002)