Photonic Nanojets from microspheres: A step to superfocusing of light

Summary form only given: Diffraction in optics is the main wave process which sets the limiting size for the localization of an optical field in its scattering from an obstacle or its passage through a focusing system. For a collecting lens with a round aperture the diffraction limit for the focusing of radiation with a plane wavefront is roughly one wavelength. This classical diffraction limit was obtained under the assumption that after the lens the light wave freely propagates to the focal region through a distance much longer than the wavelength, i.e. that the electromagnetic field diffraction is considered in the far-field zone.