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Concentric Nano Elliptical Apertures Array Tip for Intensity Enhancement in Scanning Near-Field Optical Microscopy for Imaging
  • Amirsaman Zare Andalani ,
  • Naghmeh Sadat Moayedi ,
  • Nosrat Granpayeh
Amirsaman Zare Andalani
K.N.Toosi University of Technology

Corresponding Author:[email protected]

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Naghmeh Sadat Moayedi
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Nosrat Granpayeh
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Abstract

One of the advantages of light controlling is the enhancement of its intensity in localization of the beam in the near- and far-fields. Our desire is to design a concentric nano elliptical apertures array tip (CNEAAT) for this purpose. The array tip manipulates the incident light by the nano elliptical apertures with sizes smaller than half-wavelength of the incident photons over the visible spectral range. The designed array tip generates the beam with the improved optical characteristics for maximum intensity enhancement at a special direction of far-field points. The light is steered to examine the output beam of the CNEAAT at various elevation angles in the near-field. For a special scanned impinged angle, the CNEAAT irradiation is focused on an assigned material under-test (MUT) for study of the beam enhancement. The MUT is inserted inside a cylindrical reservoir. The reservoir is inscribed by wall with n=1 and height of 40μm, includes the cross-section radius of 138nm and a metal bottom. In our design, the MUT is assumed to have real permittivity, as a sample to test the intensity enhancement of the impinged and transmission beams. The intensity enhancement obtained by the CNEAAT is anticipated comparable with the standardized apertures arrays. The design is found to be used in the numerous applications analogous to scanning near-field optical microscopy (SNOM) for imaging.