Search

We report a study of a gallium phosphide, hemispherical, solid immersion lens through the imaging of 40-nm-diam fluorescent dye balls. A spatial resolution as small as 139 nm has been achieved at a wavelength of 560 nm, which is equivalent to a diffraction-limited system of numerical aperture 2.0. This resolution is a 33% improvement over conventional oil immersion objectives and previously reported solid immersion lenses, which typically have a numerical aperture around 1.5.

We report a near-field scanning optical microscope using a solid immersion lens having a sharp tip that is mounted to a cantilever. The sharp tip allows the sample to enter the near field of the illumination. The cantilever provides sensitive control of forces. We describe two types of near-field optical contrast, interference and reflection, that simultaneously measure surface topography and reflectivity. Using a super-hemispherical lens with index n=2.2 and 442 nm illumination, the microscope resolves optical features smaller than 150 nm, a factor of 2 improvement over a conventional optical microscope.