  Engineering of intensity and direction of radiation from a single quantum
emitter by means of structuring of their environment at the nanoscale is at the
cornerstone of modern nanophotonics. Recently discovered systems exhibiting
spin--orbit coupling of light are of particular interest in this context. In
this Letter, we have demonstrated that asymmetrical excitation of a high-index
subwavelength dielectric nanoparticle by a point dipole source located in a
notch at its surface results in formation of a chiral near field, which is
similar to that of a circularly polarized dipole or quadrupole. Using numerical
simulations, we have shown that this effect is the result of a higher multipole
(quadrupole and octupole) modes excitation within the nanoparticle. We have
applied this effect for unidirectional excitation of dielectric waveguide and
surface plasmon-polariton modes. We have achieved the value of front--to--back
ratio up to 5.5 for dielectric waveguide and to 7.5 for the plasmonic one. Our
results are important for the integrated nanophotonics and quantum information
processing systems.

Optics