Atomic and molecular systems for radiation thermometry.

Area of Science:

• Quantum Physics
• Metrology
• Atomic Physics

Background:

• Atoms and molecules offer unique properties for developing precise measurement standards and sensors.
• Quantum mechanics dictates atomic properties, making them ideal for fundamental measurements.
• Radiative temperature measurement is crucial across scientific and industrial applications.

Purpose of the Study:

• To introduce a novel concept for creating radiative temperature standards and sensors using atoms and molecules.
• To present experimental results from two distinct atomic-based temperature measurement systems.
• To detail the theoretical framework, including rate equation models, for interpreting experimental data.

Main Methods:

• Utilizing laser-cooled 85Rb Rydberg atoms in a cold atom thermometer (CAT) to probe blackbody radiation (BBR) near 130 GHz.
• Employing a compact BBR atomic sensor (CoBRAS) with 85Rb vapor to monitor fluorescence related to BBR near 24.5 THz.
• Applying rate equation models to interpret the interaction between atomic transitions and BBR.

Main Results:

• The CAT achieved a primary temperature measurement with approximately 1% uncertainty, with potential for further reduction.
• The CoBRAS demonstrated excellent relative precision of u(T) ≈ 0.13 K in measuring the blackbody spectrum.
• Both experiments showcase the feasibility of atomic systems for precise radiative temperature determination.

Conclusions:

• Atoms and molecules can serve as foundational elements for new standards and sensors of radiative temperature.
• The developed cold atom thermometer and compact BBR atomic sensor represent significant advancements in primary thermometry.
• These atomic-based approaches offer a promising path towards redefining temperature measurements in line with quantum principles.