Higher resolution Artist’s impression of the zeptojoule bolometer. The normal-metal nanowire runs through the centre of the device and absorbs microwave energy. The fin-like structures are superconducting and create a series of Josephson junctions that function as a thermometer. (Courtesy: Ella Maru Studio)"> Higher resolution Artist’s impression of the zeptojoule bolometer. The normal-metal nanowire runs through the centre of the device and absorbs microwave energy. The fin-like structures are superconducting and create a series of Josephson junctions that function as a thermometer. (Courtesy: Ella Maru Studio)

A bolometer that can measure absorbed energy at a resolution of less than a zeptojoule (10 −21 J) has been unveiled by Mikko Möttönen and colleagues at Finland’s Aalto University.…