Fabrication of solid immersion lens with gold nanoparticles by surface tension mold technique

Abstract

A super-hemispherical (i.e. a truncated spherical) glass lens with gold (Au) nanoparticles was obtained using a surface tension mold (StM) technique. Recently, surface plasmon of noble metal nanoparticle has attracted a considerable amount of interest because it is extremely sensitive to the properties of the materials attached to its surface. On the other hand, in the field of high-resolution microscopy, solid immersion lenses (SILs) with super-hemispherical shape have received much attention because it is a convenient and powerful means of improving both the spatial resolution and the light collection efficiency. A combination of the SIL and the Au nanoparticles could be very suitable for use in surface plasmon microscopy. In this study, Na₂O-CaO-SiO₂ glass was heated on Au-coated glassy-carbon substrate up to 800 °C. The obtained glasses were found to have super-hemispherical shape, and the Au nanoparticles were deposited on its bottom planar surface. The effects of the deposition condition of Au on the distribution of Au nanoparticles and the shape of glass were investigated, and the surface plasmon resonance absorption spectra from the obtained samples were measured.