Further studies of modulated light in a double resonance experiment

Abstract

This is an investigation, at low frequencies, of the modulation of fluorescent light which has already been found a t higher frequencies in a double resonance experiment. In the earlier work, in which the frequency of magnetic resonance was of order 10 Mc/s, the Zeeman levels of the excited atom s were well separated compared with their natural width (1 M c/s): in the present work they are completely unresolved at the centre of the magnetic resonance, which is studied a t 1 kc/s. The principal resonance phenomena are observed as before under the new conditions: they are centred on a field near to zero, while their width is greater than 1G. New resonance phenomena are also studied, which do not appear when the resonance frequency is greater than the natural width of the levels. A theory, previously published, is applied to predict the form of the new resonance curves. An identical result is predicted by the use of a classical model.