The present invention relates to a deuterated polyimide, the backbone of which comprises an alternation between: at least one repeat unit corresponding to the following formula (I): ##STR00001## in which: Y represents a single bond or a spacer group; and at least one repeat unit corresponding to the following formula (II): --A.sup.1--Z-- (II) in which: A.sup.1 represents a perdeuterated aromatic group comprising from 6 to 10 carbon atoms; Z represents a single bond or a group chosen from --O--C.sub.6D.sub.4--, --CO--C.sub.6D.sub.4-- and --C.sub.6D.sub.4--. These polyimides are used in particular as materials which are transparent within the region from 2500 to 3500 cm.sup.-1, for example in laser devices.