Microsphere-assisted imaging of sub-diffraction-limited features

Observation of nanoscale elements through an optical microscope is often restricted by the resolving power of the optical system. Indeed, a white-light microscope allows the visualisation of objects having a size that is only just greater than half of the wavelength of the illumination used, in ideal cases, such as features of MOEMS- based components. In reality, imperfections or misalignment of the optical components makes this resolution limit worse. In 2011, Wang et al. introduced experimentally the phenomenon of two-dimensional super-resolution imaging through a glass microsphere. They showed that microsphere-assisted microscopy distinguishes itself from others by being able to perform label-free and full-field acquisitions. In addition, with only slight modifications of a classical white-light microscope, microsphere-assisted microscopy makes it possible to reach a lateral resolution of a few hundred nanometers. Recently, we successfully demonstrated the label-free combination of microsphere- assisted microscopy with interferometry. This work aims to compare performance of 2D imaging (microsphere- assisted microscopy) with 3D imaging (microsphere-assisted interference microscopy).