Suspended-membrane thermal detector comprising a deformable absorber

A thermal detector adapted for detecting electromagnetic radiation, comprising:

• a substrate;
• a reflector of said electromagnetic radiation;
• a three-dimensional structure configured to detect said electromagnetic radiation, suspended above the substrate and thermally insulated from the substrate, comprising:
• a membrane comprising a thermometric transducer,
• an absorber of said electromagnetic radiation,
• resting on the membrane and partly spaced from the latter, and connected thermally to the thermometric transducer,
• spaced with respect to the reflector so as to form a quarter-wave interference cavity for electromagnetic radiation,
• wherein the absorber is:
• formed on the basis of a shape-memory alloy having an inverse martensitic transformation of a martensitic phase into an austenitic phase of said alloy starting from an austenite start temperature As, and
• configured to have:
• a detection configuration when its temperature is less than or equal to a first threshold temperature T1, in which it extends in a flat manner in a plane parallel to the reflector, and
• a cooling configuration when its temperature is above a predetermined second threshold temperature T2 equal to the austenite start temperature As, in which it extends at least partly in a curved manner with respect to a plane parallel to the reflector.