Abstract: An interband cascade laser amplifier medium (M) having a number of cascades (C) strung together along a transport direction (T) of charge carriers and each having an electron injector region (I), an amplifier region (V) and an electron collector region (K), wherein the amplifier region (V) has a hole quantum film (1) having a first semiconductor material and an electron quantum film (2) having a second semiconductor material, and wherein the electron collector region (K) has at least one collector quantum film (4) having a third semiconductor material and separated by a first barrier layer (3), and the electron injector region (I) has at least one injector quantum film (5) having a fourth semiconductor material and separated by a second barrier layer (3).