Light can be used to measure temperature in many settings, says Prof. Graham Machin of the National Physical Laboratory – from healthcare to manufacturing processes for iron and steel, glass and paper.

He describes research under way at the Universities of Strathclyde and Glasgow that aims to revolutionise the practice of thermometry – including measuring microchip temperatures with sensors smaller than the diameter of a human hair.

Thermal imaging (measuring skin temperature with photons!) to prevent diabetic foot ulceration