Patent ID: 8681830

Claim:
An interband cascade laser amplifier medium comprising: an amplifier region (V) comprising: a hole quantum film ( 1 ) comprising a first semiconductor material; and an electron quantum film ( 2 ) comprising a second semiconductor material; an electron collector region (K) comprising at least one collector quantum film ( 4 ) comprising a third semiconductor material, the at least one collector quantum film being separated from an adjacent quantum film by a first barrier layer ( 3 ); and an electron injector region (I) following the electron collector region and comprising at least one injector quantum film ( 5 ) comprising a fourth semiconductor material, the at least one injector quantum film being separated from an adjacent quantum film by a second barrier layer ( 3 ), wherein: the first semiconductor material of the hole quantum film ( 1 ) is a III-V compound semiconductor comprising at least four elements, wherein at least two of the elements are selected from Ga, In and Al, and wherein at least two of the elements are selected from As, Sb, P and N.