Laser Excitation of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Th</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>229</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> Nuclear Isomeric Transition in a Solid-State Host
ROBERT ELWELL, Christian Schneider, J. Jeet, J. E. S. Terhune, Harry W. T. Morgan, Anastassia N. Alexandrova, H. B. Tran Tan, Andrei Derevianko, Eric R. Hudson
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 redshifted fluorescence that decays with a timescale of a few seconds. The second is a narrow, laser-linewidth-limited spectral feature at 148.382 19(4)_{stat}(20)_{sys} nm [2020 407.3(5)_{stat}(30)_{sys} GHz] that decays with a lifetime of 568(13)_{stat}(20)_{sys} s. This feature is assigned to the excitation of the ^{229}Th nuclear isomeric state, whose energy is found to be 8.355 733(2)_{stat}(10)_{sys} eV in ^{229}Th:LiSrAlF_{6}.