https://phys.org/news/2022-05-method-exploring-nano-world.html

Objects with a diameter smaller than one micrometer (nanoparticles) are difficult to measure and characterise. Viruses can be as small as 0.02 micrometers. Existing instruments, such as electron microscopes, for charaterising nanoparticles is bulky, expensive and time-consuming. Scientists have developed a new microscopy method based on interfereometry, which outperforms existing instruments. One possible application of this technique may be to identify illnesses.