Immersed transparent microsphere magnifying sub-diffraction-limited objects

The resolution of an optical microscope is restricted by the diffraction limit, which is approximately 200 nm for a white light source. We report that sub-diffraction-limited objects can be resolved in immersion liquids using a microsphere optical nanoscopy (MONS) technique. Image magnifications and resolutions were obtained experimentally and compared in different immersion liquids. We show that a 100 mu m diameter barium titanate (BaTiO3) glass microsphere combined with a standard optical microscope can image sub-diffraction-limited objects with halogen light in three different media: water, 40% sugar solution, and microscope immersion oil. In this paper, the super-resolution imaging performance has been described with the three immersion liquid types and the mechanisms are discussed with Mie theory calculation in the field of a Poynting vector. (C) 2013 Optical Society of America