Time-domain observation of optical pulse propagation in whispering-gallery modes of glass spheres.
We report picosecond time-resolved measurements of optical pulse propagation in dielectric spheres (8, 10, and 26 mm in diameter) for which the pulse duration ( approximately 2 ps) was short compared with the equatorial round-trip time within the sphere. A size-independent buildup of the leakage intensity in terms of the number of round trips was observed for each of the spheres, as were damped low-frequency oscillations superimposed upon the pulse ringdown envelope. These features of the data are interpreted as resulting from perturbative coupling of eigenmodes of the sphere and trajectory precession near the observation region.
Shaw
R W
RW
Whitten
W B
WB
Barnes
M D
MD
Ramsey
J M
JM