Abstract: Thermal-radiation imaging devices, elements and systems are described. The device comprises on a substrate (2) e.g. of sapphire semiconductor bodies or body portions in the form of parallel elongate strips (1), e.g. of cadmium mercury telluride. Biasing-electrode means (6 and 7) e.g. of gold are spaced on the strips (1) for causing a bias current predominantly of majority charge carriers to flow along each strip (1). The bias current supports an ambipolar drift of radiation-generated free minority carriers in the opposite direction. At the area of read-out means (8) in the drift path each strip (1) branches into two parts separated by a slot (13) parallel to the strip (1). One part (11 in FIG. 2) provides the continuation of the drift path, while a read-out connection comprises the other part (12 in FIG. 2) and is separated by the slot (13) from the adjacent biasing-electrode means (6 or 7).