Interaction between electromagnetic and elastic waves in a borosilicate glass at low temperatures

Abstract
Evidence has been obtained of the mutual interaction of 9 GHz electromagnetic and elastic waves in a glass at 1.5 K. These experiments prove that some two-level systems (T.L.S.) have a double nature, an explanation of which is proposed. It has been found that the T.L.S. are electromagnetically saturated by a field higher than εc = 103 V m-1