Laser Mössbauer spectroscopy of 229 Th in CaF 2
Year: 2026
Type: article
Abstract: Mössbauer spectroscopy is widely used in chemistry, geology, and solid-state physics to probe the local physical and chemical environment of nuclei in materials. Here, we extended this technique into the optical range using a vacuum ultraviolet laser to probe the low-energy nuclear transitions of thorium-229 ( 229 Th) doped in calcium fluoride (CaF 2 ) crystals. We discovered four distinct doping sites for the thorium ions, determined the characteristic electric field gradients emerging from the interaction with the host crystal, and identified the microscopic structure of the two dominant configurations. Site-selective laser excitation enabled the study of the isomeric state lifetime and laser-induced quenching for all sites. This technique provides a powerful probe of the nuclear environment, yielding foundational data for designing future solid-state nuclear clocks.
Source: Science
Authors: Takahiro Hiraki, Takahiko Masuda, Sayuri Takatori, Fabian Schaden, Michael Bartokos, Kjeld Beeks, Yuta Fukunaga, Andreas Grüneis, Ming Guan, Georgy Kazakov, Thomas LaGrange, Adrian Leitner, Ira Morawetz, Ryoichiro Ogake, Koichi Okai, Martin Pimon, Martin Pressler, Thomas Riebner, Noboru Sasao, Felix Schneider, Thorsten Schumm, Kotaro Shimizu, Luca Toscani de Col, Tomas Sikorsky, Akihiro Yoshimi, Koji Yoshimura
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Revealing the Thorium-229 isomer by active pumping, A quantum chemical approach to dynamic properties of real materials, Coherent Optical Metrology Beyond Dipole-Allowed Transitions, Realization of Coherent Nuclear Manipulation with Lasers: Towards the Development and Application of a Nuclear Clock", 物理定数恒常性の測定感度向上へ向けた原子核時計の研究, G2651223556, Thorium-229 nuclei for the development of solid-state nuclear clocks, G3404197642, G500496836, Nuclear Clock: Exploring Fundamental Physics with an Innovative Probe, 原子核時計が切り拓く時空計測フロンティア, G6528122635, Nuclear relaxation of the Thorium-229 isomer in a crystal, G8656393412, G9000309119
OpenAlex ID: W7203823665