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arXiv · 2404.12311

Laser excitation of the $^{229}$Th nuclear isomeric transition in a solid-state host

R. Elwell·Christian Schneider·Justin Jeet·J. E. S. Terhune·H. W. T. Morgan·A. N. Alexandrova·H. B. Tran Tan·Andrei Derevianko·Eric R. Hudson
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Abstract

LiSrAlF$_6$ crystals doped with $^{229}$Th are used in a laser-based search for the nuclear isomeric transition. Two spectroscopic features near the nuclear transition energy are observed. The first is a broad excitation feature that produces red-shifted fluorescence that decays with a timescale of a few seconds. The second is a narrow, laser-linewidth-limited spectral feature at $148.38219(4)_{\textrm{stat}}(20)_{\textrm{sys}}$ nm ($2020407.3(5)_{\textrm{stat}}(30)_{\textrm{sys}}$ GHz) that decays with a lifetime of $568(13)_{\textrm{stat}}(20)_{\textrm{sys}}$ s. This feature is assigned to the excitation of the $^{229}$Th nuclear isomeric state, whose energy is found to be $8.355733(2)_{\textrm{stat}}(10)_{\textrm{sys}}$ eV in $^{229}$Th:\thor:LiSrAlF$_6$.

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R. Elwell, Christian Schneider, Justin Jeet, J. E. S. Terhune, H. W. T. Morgan, A. N. Alexandrova, H. B. Tran Tan, Andrei Derevianko, Eric R. Hudson. 2024-04-18. Laser excitation of the $^{229}$Th nuclear isomeric transition in a solid-state host. https://arxiv.org/abs/2404.12311

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