Towards Next-Generation X-ray Imaging with Tunable X-Rays and Quantum Recoil by Prof Wong Liang Jie

IAS@NTU Discovery Science Seminar by Nanyang Assistant Professor Wong Liang Jie (29 March 2023, NTU LT3):
Quantum recoil - the defiance of classical physics by photons spontaneously emitted from free electrons - is not only a fundamental phenomenon but also of direct importance to the practical development of versatile, compact, coherent X-ray sources. First postulated by Russian Physicist and Nobel Laureate Vitaly Ginzburg in 1940, quantum recoil has remained experimentally elusive. In this talk, Prof Wong discussed the quest for the holy grail of a versatile, compact X-ray source, and the promise of free-electron-driven van der Waals materials in achieving this goal. He described how his team's quest led them surprisingly to an experimental demonstration of quantum recoil. Despite being a quantum phenomenon, quantum recoil is observable even at room temperature and in the presence of external scattering events. They outline plans to measure regimes where quantum recoil manifests strongly, resulting for example in the emission of a classically predicted X-ray photon as a very low energy photon. Their findings pave the way to safer and more discerning X-ray imaging technology that could be disruptive in a broad range of applications, from manufacturing inspection to medical imaging.