Mirror-enhanced super-resolution microscopy

A simple method that involves swapping a microscope slide with a mirror improves the resolution of laser-scanning microscopy techniques. Many super-resolution microscopy techniques obtain high resolutions by squeezing the light illuminating the sample in to a very confined region. Peng Xi of Peking University in China and co-workers have devised a simple and versatile way to confine the exciting light to a diameter of ∼110 nanometres (about 1/6 the diffraction limit) — putting the sample on a mirror rather than a slide. This causes the incident light to interfere with its reflection, resulting in a narrower illumination field. By combining this technique with stimulated emission depletion nanoscopy, the team could image the tubular structure of a virion. This method is particularly well-suited for biological specimens as it does not involve high laser powers.