Light: Science and Applications is an open access journal that publishes the highest quality articles in basic and applied optics and photonics.
Optical microscopy is regarded as one of the most significant tools in the development of science and technology. Since its initial invention in the late sixteen century, the microscope has earned a reputation of enabling the visualization of objects (or fine structures) that are usually invisible to the naked eye, thus shaping various disciplines such as biology, medicine and materials science. The capability of this technique, to sketch the boundary of microstructures, measure surface morphology and localize specified molecule distributions in vivo, has driven modern research. Without optical microscopy, our knowledge of the ‘microworld’ would be severely impaired.
The resolution of conventional optical equipment is always restricted by the diffraction limit, and improving on this was previously considered improbable. Optical super-resolution imaging, which has recently experienced rapid growth and attracted increasing global interest, will result in applications in many domains, benefiting fields such as biology, medicine and material research. This review discusses the contributions of different researchers who identified the diffractive barrier and attempted to realize optical super-resolution. This is followed by a personal viewpoint of the development of optical nanoscopy in recent decades and the road towards the next generation of optical nanoscopy.