What is it about?
Measuring the temperature of atoms is important for many areas of science, from precision measurements to quantum technologies. One way to do this is by shining laser light on atoms and studying how they absorb and scatter that light. In our work, we use two special colors of laser light (called D1 and D2 transitions) to study how atoms respond at different temperatures. By analyzing the patterns in the light signals, we show that these transitions can be used as sensitive thermometers for atoms. This approach also provides insights for applications such as laser cooling, frequency stabilization of lasers, and developing new tools for quantum science.
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Why is it important?
We pioneer the use of potassium’s D1 and D2 transitions for atomic thermometry via modulation transfer spectroscopy—a previously unexplored application. The small hyperfine splitting in potassium creates distinct crossover features, enabling highly sensitive temperature measurements even without closed transitions. Our study offers a simple, non-invasive thermometry tool for quantum technology platforms using potassium, such as quantum sensors and cold atom systems, enhancing precision in thermal management and system optimization.
Perspectives
From my perspective, this work represents an exciting convergence of fundamental atomic physics and practical quantum engineering. I was particularly struck by how clearly the modulation transfer signals emerged in potassium—a system often overlooked due to its lack of closed transitions—demonstrating that robust spectroscopic tools can be developed even in “non-ideal” atomic systems. It’s deeply satisfying to see crossover resonances, often treated as spectral complications, become the foundation for a new approach to atomic thermometry. This not only opens a simple path to in-situ temperature sensing in potassium-based quantum devices but also encourages a second look at other “complex” atomic systems for metrological applications.
Prosenjit Majumder
Read the Original
This page is a summary of: Atomic thermometry with modulation transfer spectroscopy of potassium D1 and D2 transitions, Journal of Applied Physics, August 2025, American Institute of Physics,
DOI: 10.1063/5.0280709.
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