Three-dimensional Nanoscale Far-field Focusing of Radially Polarized Light by Scattering the SPPs with an Annular Groove

State Key Laboratory of Optical Technologies for Microfabrication, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
Optics Express (Impact Factor: 3.49). 07/2010; 18(14):14664-70. DOI: 10.1364/OE.18.014664
Source: PubMed


Three-dimensional (3D) nanoscale focusing of radially polarized light in far field by a simple plasmonic lens composed of an annular slit and a single concentric groove is reported. The numerical calculations reveal that the incident light is coupled to surface plasmon polaritons (SPP) by the annular slit and a focal spot with a size less than a half of the illumination wavelength is formed in the far field due to the constructive interference of the scattered light by the groove. More importantly, the focal length can be modulated by changing the groove diameter. This structure provides an admirable choice for the nano-optical devices.

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    • "EVERAL research works have regarded the use of radial polarization as very suitable to achieve the best focusing performance in terms of spot size [1]–[3], for which Fresnel Zone Plates (FZP) is one of the options that provides interesting applications in different spectrum ranges. Microzone plates have been proposed for superfocusing at visible regime [4]–[6] analyzing their properties through the finite-difference time-domain (FDTD) method, which has also been applied [7] to study the influence of propagating and evanescent waves on the focusing properties of FZPs. "
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