Localized surface plasmon microscope with an illumination system employing a radially polarized zeroth-order Bessel beam

We propose an imaging principle that employs a radially polarized zeroth-order Bessel beam in the illlumination system of the localized surface plasmon microscope. The illumination system enables the microscope to visualize a refractive index distribution on a substrate fabricated in the Kretschmann configuration by the measurement of reflected intensity. The experimentally observed image of a particle reveals that the spatial resolution reaches the optical diffraction limit. The proposed principle can contribute to increase the imaging speed of localized surface plasmon microscopy by use of a beam scanning device.