Electromodulation of the Optical Properties of Thallium-Activated Potassium Bromide

The absorption spectrum of KBr:Tl crystals has been investigated using an ac electric field (2×${10}^4$ V/cm, rms). The change of the absorption coefficient, versus photon energy, supports the validity of Henry, Schnatterly, and Slichter's theory concerning the zeroth-moment conservation. It is also shown that the absorption intensity of the $B$ band is supplied, almost entirely, by the $A$ band.