Hanle effect

The Hanle effect is a reduction in the polarization of light when the atoms emitting the light are subject to a magnetic field in a particular direction, and when they have themselves been excited by polarized light. The Hanle effect is a reduction in the polarization of light when the atoms emitting the light are subject to a magnetic field in a particular direction, and when they have themselves been excited by polarized light. It is named after Wilhelm Hanle, who first described it in Zeitschrift für Physik in 1924. Attempts to understand the phenomenon were important in the subsequent development of quantum physics.