  We propose a novel concept for efficient dynamic tuning of optical properties
of a high refractive index subwavelength nanoparticle with a magnetic Mie-type
resonance by means of femtosecond laser radiation. This concept is based on
ultrafast generation of electron-hole plasma within such nanoparticle,
drastically changing its transient dielectric permittivity. This allows to
manipulate by both electric and magnetic nanoparticle responses, resulting in
dramatic changes of its extinction cross section and scattering diagram.
Specifically, we demonstrate the effect of ultrafast switching-on a Huygens
source in the vicinity of the magnetic dipole resonance. This approach enables
to design ultrafast and compact optical switchers and modulators based on the
"ultrafast magnetic light" concept.
