Investigation of theA,B, andCBands in KBr: In by Means of Electromodulated Optical Absorption

The effect of an electric field (∼ ${10}^4$ V/cm, rms) on the $A$, $B$, and $C$ absorption bands of potassium bromide-indium phosphors has been studied. The $A$ and $C$ bands are composed of three subbands, while the $B$ band exhibits a doublet structure. A correlation has also been found between the absorption intensities of these bands, the decrease in the $A$ and $B$ bands being compensated by the increase in the $C$ band. A perturbative treatment has been used to explain the observed variation of the zeroth-order moments of $A$, $B$, and $C$ bands.