Thermal infrared sensors are disclosed for the detection of an incident infrared flux. The sensors include an absorber each including an absorption layer and a thermal sensing element. The incident infrared flux is absorbed by the absorption layer. Heat generated by the absorption is detected by the thermal sensing element such as a thermistor. The absorber is supported above a substrate by supports and bridges, reducing heat transfer from the absorber to the substrate. The supports and bridges include electrical connections to the absorber and the substrate. The supports and bridges are located beneath the absorber so that a large proportion of the area of the absorber is available to absorb the incident flux. Imaging devices including arrays of such sensors and fabrication methods for the sensors and imaging devices are also disclosed.