Strong Magnetic Response of Optical Nanofibers

We introduce a new platform to achieve a strong magnetic response in optical fibers with nanoscale dimension. We reveal that for a coupled dipole-fiber system an electric dipole placed near an optical nanofiber can produce strong magnetic response. We show that the magnetic and electric response of such a system depends on the orientation of the dipole source with respect to the fiber. Using the multipole expansion method, we demonstrate that it is possible to suppress the electric response and preferentially enhance the magnetic resonance of a coupled dipole-fiber system, in such a way that the energy in the magnetic mode can be made 2 orders of magnitude higher than that of the electric mode of the system. This nanophotonic system opens up new possibilities to develop low-dimensional nanodevices with enhanced magnetic response.