RRI Researchers Achieve Breakthrough in Storing Light with Potassium for Quantum Applications

The RRI team's work further supports the validity of the quantum master equation (QME) in studying light-matter interactions, even in cases with small ground energy level separation.

Experimentalists at the Raman Research Institute (RRI) have made significant progress in storing light using Potassium atoms, opening the door to advanced applications in quantum sensors and communication protocols. This development could enhance India's growing research and development efforts in quantum technologies. Traditionally, scientists have worked with alkali metals like Rubidium and Cesium for optical studies, but Potassium, though promising, has posed considerable challenges.

 

A team led by Gourab Pal and Dr. Saptarishi Chaudhuri from the Quantum Mixtures (QuMix) lab at RRI, in collaboration with Prof. Subhasish Dutta Gupta from TIFR Hyderabad, has now succeeded in leveraging Potassium atoms for breakthrough results in Electromagnetically Induced Transparency (EIT) studies. EIT is a quantum interference phenomenon that allows for controlling light using light, modifying the optical properties of an atomic medium. The team used highly stabilized laser sources to create quantum coherence in Potassium atoms, resulting in the ability to manipulate the transmission of light beams in ways previously not achieved with other alkali atoms.

 

For the first time, the researchers observed three resonance lines in a single absorption spectrum in Potassium vapor—a novel feature, as similar experiments with Rubidium or Cesium typically show just one line. The presence of additional transparency windows is attributed to the hyperfine ground states in Potassium atoms, allowing for multiple resonance pathways. The ability to store light in atomic media through quantum coherence opens up a wide array of futuristic applications, including quantum memory and quantum communication.

 

The findings, published in Physica Scripta, offer new possibilities for ultra-precise frequency stabilization of lasers, especially in situations where spectroscopic references are unavailable, reducing the need for costly wavelength meters. The RRI team's work further supports the validity of the quantum master equation (QME) in studying light-matter interactions, even in cases with small ground energy level separation. Their theoretical modeling with QME aligns with real-world quantum systems, enhancing our understanding of coherent atomic media and advancing quantum protocols. This breakthrough brings India one step closer to the development of high-precision quantum technologies, enabling applications in both fundamental research and industry.