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Here, we demonstrate a strategy that two orthogonal modes in a dielectric cavity can efficiently couple with each other through the bridging effect of a plasmonic antenna. In such a dielectric-antenna hybrid system, a plasmonic antenna can coherently interact with both modes of the dielectric cavity, which brings sufficient coherent energy transfers between the two orthogonal modes. Specifically, a broad electromagnetic mode and a narrow whispering gallery mode (WGM) in a subwavelength silicon disk are considered, where they cannot directly interact with each other through near-field couplings. By introducing a plasmonic antenna, coherent energy transfer between the above two modes occurs, which is confirmed by both far-field spectra and near-field distributions. More investigations show that spectral and spatial overlaps between the involved modes can largely affect energy transfer behaviors. Those overlaps are highly dependent on various parameters of the system. The WGM response in the hybrid system can even exceed that of an individual disk. Our proposed strategy can be extended to other similar systems and the modified optical responses can find applications in enhanced light-matter interactions. [ABSTRACT FROM AUTHOR]

Accurate determination of the electrostatic force exerted on multipole moments is essential in comprehending the interaction between charged bodies and dielectric layers. A comprehensive solution is presented in this study for the calculation of the electric potential, field, and force generated by n th-order electric multipole above a semi-infinite dielectric body covered by a dielectric layer using the image multipole method. The present study investigates the impact of dielectric thickness, permittivity, and separation distance on the electrostatic interaction between an electric multipole moment and a semi-infinite dielectric body. The calculation results indicate that as the thickness of the dielectric layer increases and the dielectric constant of the surrounding medium surpasses that of the dielectric layer, the electrostatic attractive force undergoes a transition to a repulsive force. The magnitude of the electrostatic force acting on a n th-order electric multipole moment is directly proportional to the square of the value of the electric multipole moment and inversely proportional to the 2 (n +1) power of the distance. [ABSTRACT FROM AUTHOR]