Efficient method for the calculation of the optical force of a single nanoparticle based on the quasinormal mode expansion
Abstract
An efficient method for the calculation of the optical force of a single nanoparticle is proposed based on the expansion of quasinormal modes (QNMs), which are eigensolutions of sourcefree Maxwell's equations with complex eigenfrequencies. In this method, the optical force is calculated by integrating the Maxwell stress tensor (MST) over a closed surface encompassing the nanoparticle. The electromagnetic (EM) field required for evaluating the MST is computed by a rigorous modal analysis, in which the EM field is expanded onto a small set of QNMs. Once the QNMs of the nanoparticle are solved, their excitation coefficients are obtained analytically. This means that additional fullwave computations are not required if the nanoparticle's location and the wavelength or distribution of the excitation field vary. Comparisons with fullwave numerical calculations of optical force evidence the high efficiency and accuracy of our formalism.
 Publication:

Optics Letters
 Pub Date:
 June 2021
 DOI:
 10.1364/OL.426423
 Bibcode:
 2021OptL...46.2658Q