Controlled modification of the expansion order as a tool in mie computations.
In the framework of Mie theory the involved electromagnetic fields are expanded in an infinite series of multipoles. In numerical computations the summation has to be terminated after a finite number of terms (the expansion order N), which unavoidably produces errors. On the other hand, it is known that the contributions of terms of order l with x <l < N, where x is the dimensionless size parameter, are highly localized, i.e., these contributions appear as sharp peaks in resonance spectra. We show that it is possible to specify the expansion order in a controlled manner to extract certain features from Mie spectra. This controlled modification of the expansion order can be used as a high-pass, low-pass or bandpass filter. Formulas that serve as linewidth (frequency) and resonance-order filters are given, and their usage is demonstrated.
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Kaiser
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Schweiger
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