Splitting of low-Q Mie resonances in high-density alumina spheres with dielectric constant ε≈9.6 is observed. The spheres have a shape distortion parameter value that ranges over 2 orders of magnitude, i.e., from 8×10−5 to 10×10−3. Splitting is observed at the (magnetic or TE) b4, 1 (Q≈425), b5, 1 (Q≈1700), and b6, 1 (Q≈ 5650) resonances. No splitting of the b3, 1 or (electric or TM) a4, 1 and a5, 1 resonances is observed. The b5, 1 resonance is studied extensively. The expected broadening or reduced Q of the resonances that is due to overlapping of the lines split by shape distortion is generally not observed. It is also found that it is easier to observe splitting in the spheres with the smallest shape distortion. This suggests that the mechanism responsible for the observed splitting competes with the shape splitting in such a way that destructive interference results.
© 1998 Optical Society of America
Lawrence A. Ferrari and Joseph B. Comunale, "Splitting of low-Q Mie resonances," J. Opt. Soc. Am. A 15, 1858-1866 (1998)