A Journey of Exploring Atomic Cesium 8S Energy Level
Absolute frequency of the cesium atom 8S level offers an excellent basis for testing fundamental principles in physics, such as the QED verification via frequency comparison with the hydrogen atom, the parity non-conservation calculation and possible quark mass variation using the feature of heavy cesium nucleus. Eight years ago, we started with 8S-state referenced laser stabilization , and promoted it later to be a hand-sized optical frequency reference . In 2013, we measured the level energy with high precision  in that the cesium cell comparisons surprised people in atomic physics . In 2014, we realized a dual-comb laser system in which the comb frequency referred to cesium atom 8S level . In 2015, we demonstrated novel quantum interference for laser stabilization and cesium cell comparison . All the aforementioned works only focus on ONE hyperfine level of atomic cesium 8S state.
 C.-Y. Cheng, C.-M. Wu, G.-B. Liao and W.-Y. Cheng*,Opt. Lett., 32, 563 (2007).
 Y. -Y Chen, T. -Wei Liu, C. -M Wu, C. -C Lee, C. -K Lee and W. –Y Cheng*,Opt. lett. 36, 76 (2011)
 Chien-Ming Wu, Tze-Wei Liu, Ming-Hsuan Wu, Ray-Kung Leeand Wang-Yau Cheng*,Opt. Lett. 38,3186 (2013).
 This work was selected as ”Spotlight on Optics” by Optical Society of America (OSA), see http://www.opticsinfobase.org/spotlight/summary.cfm?URI=ol-38-16-3186
 Tze-Wei Liu, Chien-Ming Wu, Yen-Chu Hsu, Wang-Yau Cheng*, Appl. Phys. B 117, 699 (2014)
 Chien-Ming Wu, Tze-Wei Liu and Wang-Yau Cheng*, Phys. Rev. A 2, 042504 (2015).
Dr. Wang-Yau Cheng
- Associate Professor, Department of Physics, National Central University, Taiwan
- Faculty Member, Taiwan International Graduate Program in Molecular Science and Technology (MST)