Direct observation of a highly forbidden optical transition in Sm:SrF${}_2$

Abstract

The $4f^6$ ${}^7{F}_0$ $\to 4f^6$ ${}^5{D}_0$ intra-configuration transition in Sm:SrF${}_2$ is forbidden for Sm${}^{2+}$ ions in the octahedrally symmetric substitution sites in SrF${}_2$. We report the direct observation of this transition using laser-induced fluorescence at cryogenic temperatures, and measurements of the excited state lifetime and the excitation cross section. To the best of our knowledge, this optical transition has the longest lived excited state ever observed in a solid.

arXiv comment5 pages, 6 Figures

References in corpus (7)

• Quantum Memories. A Review based on the European Integrated Project "Qubit Applications (QAP)"
• Isolating and enhancing the emission of single erbium ions using a silicon nanophotonic cavity
• Coherent properties of single rare-earth spin qubits
• Frequency-stabilization to 6x10^-16 via spectral-hole burning
• Laser frequency stabilization based on steady-state spectral-hole burning in Eu${}^{3+}$:Y${}_2$SiO${}_5$
• Absolute and relative stability of an optical frequency reference based on spectral hole burning in Eu${}^{3+}$:Y${}_2$SiO${}_5$
• Characteristics of long-lived persistent spectral holes in $E{u}^{3+}:Y_{2}Si{O}_5$ at $1.2K$