The NIST Atomic Thermometers program is developing quantum-based sensors to measure temperature using atomic transitions. These sensors use the way atoms absorb or emit blackbody radiation (BBR) to determine temperature. Two main approaches are being explored: CoBRAS and CAT. CoBRAS uses a thermal vapor of atoms excited by a laser to detect BBR, measuring temperature based on fluorescence intensity ratios. This method has achieved a temperature resolution of 0.04% in the range of 308 K to 344 K, with potential for even greater accuracy with improved design.
The second approach, CAT, uses cold atoms trapped in a magneto-optical trap and excited to Rydberg states. These atoms interact with BBR, and their population changes are measured using selective field ionization. This method has demonstrated a temperature resolution of 0.5% in the range of 297 K to 338 K. While less precise than CoBRAS currently, improvements in detection techniques could greatly enhance its accuracy. Both methods aim to replace traditional thermometers with self-calibrated, quantum-based alternatives that offer higher precision and reliability.
Source: https://www.nist.gov/programs-projects/atomic-thermometers
Keywords: Quantum Thermometry, Blackbody Radiation, Atomic Vapor Cells
