2021/09/15 by Gombojav O. Ariunbold, Vladimir A. Sautenkov, Hebin Li +7
Chemistry · Physics and Astronomy · #Advanced Fiber Laser Technologies #Atomic physics #Caesium #Chemistry #Excited state #Femtosecond #Ground state #Laser #Laser-Matter Interactions and Applications #Materials science #Optics #Physics #Picosecond #Quantum optics and atomic interactions #Ultrashort pulse #physics.atm-clus #physics.atom-ph
paper · pdf · doi:10.1016/j.physleta.2022.127945
7 pages, 5 figures
arxiv created 2021/09/15 · openalex created_date 2021/09/27 · openalex publication_date 2022/01/14 · arxiv updated 2022/03/02 · openalex updated_date 2026/08/05
Spontaneous emission from individual atoms in vapor lasts nanoseconds, if not microseconds, and beatings in this emission involve only directly excited energy sublevels. In contrast, the superfluorescent emissions burst on a much-reduced timescale and their beatings involve both directly and indirectly excited energy sublevels. In this work, picosecond and femtosecond superfluorescent beatings are observed from a dense cesium atomic vapor. Cesium atoms are excited by 60-femtosecond long, 800 nm laser pulses via two-photon processes into their coherent superpositions of the ground 6S and excited 8S states. As a part of the transient four wave mixing process, the yoked superfluorescent blue light at lower transitions of 6S - 7P are recorded and studied. Delayed buildup time of this blue light is measured as a function of the input laser beam power using a high-resolution 2 ps streak camera. The power dependent buildup delay time is consistently doubled as the vapor temperature is lowered to cut the number of atoms by half. At low power and density, a beating with a period of 100 picoseconds representing the ground state splitting is observed. The autocorrelation measurements of the generated blue light exhibit a beating with a quasi-period of 230 fs corresponding to the splitting of the 7P level primarily at lower input laser power. Understanding and, eventually, controlling the intriguing nature of superfluorescent beatings may permit a rapid quantum operation free from the rather slow spontaneous emission processes from atoms and molecules.