Label-free super-resolution imaging using patchy microspheres in various mediums

The diffraction limit is a fundamental barrier in optical microscopy, restricting the smallest resolvable feature size of a microscopic imaging system. Microsphere-assisted super-resolution microscopy has emerged as a promising approach for overcoming this limit. This technique offers several advantages, including no need of fluorescent dyes, easy operation under white light illumination, and good compatibility with commercial optical microscopes. Various strategies have been proposed to enhance the imaging performance of microspheres. Recently, patchy microspheres were found to exhibit super-resolution capabilities in air with an enhanced imaging contrast. In this work, we studied the super-resolution imaging performance of patchy microspheres fully immersed in liquid. Furthermore, we demonstrated the formation of photonic hooks from patchy microspheres within a liquid environment. The findings of this study will extent the application of patchy microspheres from air to liquid immersion mode, opening up new possibilities for super-resolution imaging in liquid environment with patchy microspheres.