|In a microdiamond with a nickel-containing NV center, the duration of emission of green luminescent light after excitation with blue laser pulses decreases with increasing temperature (left to right). (Source: Université de Lyon / E. Homeyer)
Using a micrometer-sized diamond on a silicon substrate with a nitrogen-vacancy (NV) center that also contains a nickel (Ni) atom, scientists from Université Lyon (Villeurbanne, France) and the Czech Academy of Sciences (Praha, Czech Republic) are detecting temperatures between 120 K and 900 K to a resolution of better than 1 K.1
Excited with blue laser light, the NV center luminesces in the green with a lifetime that varies with temperature (but an intensity that remains constant). Future versions of such contactless microsensors could be used in aeronautics, combustion-engine research, gaseous flows, chemical reactions, and other applications.
"Our approach has the potential for very fast temperature measurements," note Estelle Homeyer and her colleagues from the Université Lyon in Villeurbanne. The microdiamonds respond within a few microseconds to the excitation laser light, while the power of the laser pulses is low enough to not disturb the temperature.
1. E. Homeyer et al., Applied Physics Letters (2015); http://scitation.aip.org/content/aip/journal/apl/106/24/10.1063/1.4921177