Antimonide based infrared detectors : a new perspective Infrared detector characterisation Antimonide based materials Type II superlattices Antimonide based infrared photodiodes Type II superlattice infrared photodiodes Infrared barrier photodetectors Cascade infrared photodetectors Coupling of infrared radiation with detector Focal plane arrays Final remarks Among the many materials investigated in the infrared (IR) field narrow gap semiconductors are the most important in IR photon detector family. Although the first widely used narrow gap materials were lead salts (during the 1950s IR detectors were built using single element cooled PbS and PbSe photoconductive detectors primary for anti missile seekers) this semiconductor family was not well distinguished. This situation seems to have resulted from two reasons: the preparation process of lead salt photoconductive polycrystalline detectors was not well understood and could only be reproduced with well tried recipes; and the theory of narrow gap semiconductor bandgap structure was not well known for correct interpretation of the measured transport and photoelectrical properties of these materials