MORPHOLOGY-DEPENDENT RESONANCES OF AN INFINITELY LONG CIRCULAR-CYLINDER ILLUMINATED BY A DIAGONALLY INCIDENT PLANE-WAVE OR A FOCUSED GAUSSIAN-BEAM

The S matrix for scattering a diagonally incident focused Gaussian bea m by an infinitely long circular cylinder is calculated, and the diago nal and off-diagonal elements of the matrix are physically interpreted . In addition, the TE and TM morphology-dependent resonances of the cy linder for plane-wave incidence are examined, and it is found that the cylinder size parameter at resonance increases as the angle of incide nce of the plane wave increases. The size parameter increase is explai ned in terms of the heuristic model of morphology-dependent resonances . The presence of both TE and TM resonances in each of the epsilon-pol arized and mu-polarized partial-wave scattering amplitudes is discusse d. This mixing is interpreted in terms of successive polarization-pres erving and cross-polarized total internal reflections of the morpholog y-dependent-resonance wave inside the cylinder. Finally, some novel pr operties of morphology-dependent resonances produced by Gaussian-beam incidence are predicted. (C) 1997 Optical Society of America.