The sharpest images ever achieved by optical means have been produced by researchers at the Max Planck Institute for Biophysical Chemistry, who have imaged clumps of bacteria just 33 nanometres across, equivalent to 1/23 of the wavelength of light used to illuminate them.
The researchers hope to achieve a resolution of around 17 nanometres, using ultraviolet light. Practical devices are expected within two or three years, which could have microlithography and optical data storage uses.