A light wave oscillates perpendicular to its propagation direction – that is what students learn in school. However, scientists of the Vienna University of Technology (TU Vienna) now perform atom-physics experiments with light oscillating in the longitudinal direction.
Storing light in a bottle is easier than one might think: Laser light can be coupled into an optical glass fiber in such a way that it does not travel along the fiber but rather spirals around it in a bulged, bottle-like section. In such a bottle microresonator light can be stored for about ten nanoseconds, corresponding to 30,000 revolutions around the fiber. This is long enough to enable interactions between the light and single atoms, which are brought very close to the fiber surface.