Photonic thermometry: upending 100 year-old paradigm in temperature metrology

For the past century, industrial temperature measurements have relied on resistance measurement of a thin metal wire or thin metal film whose resistance varies with temperature. Today’s resistance thermometers can routinely measure temperatures with uncertainties of 10 mK to 100 mK over a broad range of temperatures in varied settings ranging from a stove top to an industrial broiler to a nuclear power plant. However, for all their utility, resistance thermometers remain vulnerable to mechanical and thermal shock and attack from harsh chemicals. The resultant drift in sensor resistance necessitates frequent off-line, expensive, and time-consuming calibrations. These fundamental limitations of resistance thermometry, born of material properties, have generated considerable interest in developing photonic temperature sensors. Photonic approaches hold the promise of leveraging recent advances in frequency metrology and of achieving greater mechanical and environmental robustness. In recent years many groups including ours have demonstrated a suite of photonic devices including silicon photonic devices that can not only meet but exceed the state of art in temperature metrology