We found that the resonance positions for a weakly absorbing sphere are much different from those of a nonabsorbing sphere. The shifts of resonance positions for Qext, Qsca, and Qabs from their original resonance positions for a real refractive index are different, and the formulas to describe these different kinds of shift are given. Calculations of 12 resonance cases show that our results are quite close to those given by exact Lorenz–Mie theory. We also derive the line shapes of the different resonances and calculate values for the resonance maxima and half-width as a function of absorption.
© 1995 Optical Society of America
Original Manuscript: August 29, 1994
Revised Manuscript: November 10, 1994
Manuscript Accepted: November 15, 1994
Published: May 1, 1995
Gorden Videen, J. Li, and Petr Chýlek, "Resonances and poles of weakly absorbing spheres," J. Opt. Soc. Am. A 12, 916-921 (1995)