Microscope beats diffraction limit

Compiled by EuroPhotonics staff

A new microscope has shattered the record for the smallest object the eye can see, beating the diffraction limit of light and promising to promote understanding of the causes of many diseases.

Standard optical microscopes can see items clearly at only about 1 μm; electron microscopes can see only the surface of a cell rather than its entire structure, and there is no tool that can see a live virus.

Until now, that is.

By combining an optical microscope with a transparent microsphere, dubbed the “microsphere nanoscope,” researchers at the University of Manchester have been able to see down to 50 nm under normal light. The increased capacity means that scientists could examine live viruses inside a human cell for the first time. The findings appeared in the March 1 issue of Nature Communications (doi: 10.1038/ncomms1211).

The nanoimaging system is based on capturing optical, near-field virtual images, free from optical diffraction, and amplifying them using a microsphere – a tiny spherical particle that is further relayed and amplified by a standard optical microscope.

“Not only have we been able to see items of 50 nm, we believe that is just the start, and we will be able to see far smaller items,” said Professor Lin Li. “Theoretically, there is no limit on how small an object we will be able to see.”

Among tiny objects, the research team has also investigated anodized aluminum oxide nanostructures and the nanoscale patterns on Blu-ray DVDs, both of which were not previously visible with an optical microscope.