‘Whispering gallery’ effect controls electron beams with light

When you speak softly in one of the galleries of St Paul’s cathedral, the sound runs around the dome and visitors anywhere on its circumference can hear it. This striking phenomenon has been termed the ‘whispering gallery’ effect, and one variant is where a wave travels nearly perfectly around a structure. Researchers from the University of Göttingen have now harnessed the effect to control the beam of an electron microscope by light. Results appeared in Nature.