Physical Review A

Spectroscopic investigations of Pr3+:CaWO4 at liquid-helium temperatures

Tian-Shu Yang, Ming-Xu Su, Jian-Yin Huang, You-Cai Lv, Zong‐Quan Zhou, Chuan‐Feng Li, Guang‐Can Guo

Published Feb 6, 2023• 4 citations

Abstract

Rare-earth ions doped into low nuclear-spin density host crystals provide a promising platform for quantum information storage and processing. Calcium tungstate $({\mathrm{CaWO}}_{4})$ is an attractive host crystal because it can be isotopically enriched to provide a nuclear spin free environment. Here, we report a spectroscopic investigation of the optical transitions and hyperfine transitions of praseodymium $(^{141}\mathrm{Pr}^{3+})$ doped in ${\mathrm{CaWO}}_{4}$ at liquid-helium temperatures. The hyperfine structures of the ${}^{3}{H}_{4}$(0) and ${}^{1}{D}_{2}$(0) states are determined by spectral hole burning. The results indicate that ${\mathrm{Pr}}^{3+}$:${\mathrm{CaWO}}_{4}$ is an appealing candidate for quantum memory in quantum information processing.

DOI: 10.1103/physreva.107.022802

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Optical coherence and hyperfine structure of the 7F0-5D0 transition in EuCaWO4

An, Xiantong, Weiye Sun, Zhehao Xu +6 more

arXiv:2501.16407Jan 27, 20250 citations

Hyperfine structure, optical dephasing, and spectral-hole lifetime of single-crystalline Pr3+:La2(WO4)3

O. Guillot-Noël, Philippe Goldner, Y. Le Du +4 more

Physical Review BMay 15, 200719 citations

Spectroscopic study of hyperfine properties in Yb3+171:Y2SiO5

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Spectroscopic investigations of Eu 3+ :Y 2 SiO 5 for quantum memory applications

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Physical Review BMar 14, 201280 citations

Concentration dependence of absorption and optical and hyperfine transition dynamics in Pr 3 + :La 2 (WO 4 ) 3

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Journal of Physics B Atomic Molecular and Optical PhysicsJun 8, 20128 citations

High-resolution spectroscopy and novel crystal-field methods for rare-earth based quantum information processing

Sebastian P. Horvath

Jan 1, 20167 citations

Physical Review A

Spectroscopic investigations of Pr3+:CaWO4 at liquid-helium temperatures

Tian-Shu Yang, Ming-Xu Su, Jian-Yin Huang, You-Cai Lv, Zong‐Quan Zhou, Chuan‐Feng Li, Guang‐Can Guo

Published Feb 6, 2023• 4 citations

Publisher

Abstract

Rare-earth ions doped into low nuclear-spin density host crystals provide a promising platform for quantum information storage and processing. Calcium tungstate

({\mathrm{CaWO}}_{4})

is an attractive host crystal because it can be isotopically enriched to provide a nuclear spin free environment. Here, we report a spectroscopic investigation of the optical transitions and hyperfine transitions of praseodymium

(^{141}\mathrm{Pr}^{3+})

doped in

{\mathrm{CaWO}}_{4}

at liquid-helium temperatures. The hyperfine structures of the

{}^{3}{H}_{4}

(0) and

{}^{1}{D}_{2}

(0) states are determined by spectral hole burning. The results indicate that

{\mathrm{Pr}}^{3+}

{\mathrm{CaWO}}_{4}

is an appealing candidate for quantum memory in quantum information processing.

DOI: 10.1103/physreva.107.022802

Related papers

Optical coherence and hyperfine structure of the 7F0-5D0 transition in EuCaWO4

An, Xiantong, Weiye Sun, Zhehao Xu +6 more

Rare-earth ions doped in crystals with low nuclear-spin densities are highly promising candidates for quantum technology applications. In this study, we investigated the spectroscopic properties of the 7F0 - 5 D0 optical and the hyperfine transitions of Eu3+ ions in a CaWO4 crystal, where the nuclear spin arises solely from the 183W isotope, with a natural abundance of 14%. At a temperature of 3 K, we experimentally identified four distinct crystal field environments for Eu3+ ions in a 0.1 at.% Eu3+ doped CaWO4 crystal. The optical coherence properties of Eu3+ ions in these environments were characterized. Additionally, we resolved the hyperfine structures in the 7F0 ground state and 5D0 excited state, and determined the 7F0 ground state lifetimes using spectral hole-burning techniques. These findings highlight the significant potential of Eu3+:CaWO4 for optical quantum memory applications.Rare-earth ions doped in crystals with low nuclear-spin densities are highly promising candidates for quantum technology applications. In this study, we investigated the spectroscopic properties of the 7F0 - 5 D0 optical and the hyperfine transitions of Eu3+ ions in a CaWO4 crystal, where the nuclear spin arises solely from the 183W isotope, with a natural abundance of 14%. At a temperature of 3 K, we experimentally identified four distinct crystal field environments for Eu3+ ions in a 0.1 at.% Eu3+ doped CaWO4 crystal. The optical coherence properties of Eu3+ ions in these environments were characterized. Additionally, we resolved the hyperfine structures in the 7F0 ground state and 5D0 excited state, and determined the 7F0 ground state lifetimes using spectral hole-burning techniques. These findings highlight the significant potential of Eu3+:CaWO4 for optical quantum memory applications.

arXiv:2501.16407Jan 27, 20250 citations

Hyperfine structure, optical dephasing, and spectral-hole lifetime of single-crystalline Pr3+:La2(WO4)3

O. Guillot-Noël, Philippe Goldner, Y. Le Du +4 more

Most of the experiments related to quantum information applications, involving rare-earth doped inorganic crystals, are performed on yttrium orthosilicate single crystals. The work presented here is motivated by the search of new compounds which can be used in the field of quantum computing and/or quantum storage. Relaxation times and hyperfine structure of the $^{3}H_{4}(0)\ensuremath{\rightarrow}^{1}D_{2}(0)$ transition in 1.4% ${\mathrm{Pr}}^{3+}:{\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}$ at $4\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ have been measured by photon-echo and spectral-hole-burning techniques. The hyperfine splittings of the ground $^{3}H_{4}(0)$ and the excited $^{1}D_{2}(0)$ states are $14.9\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $24.6\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ and $5.0\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $7.3\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, respectively. An inhomogeneous linewidth of $18.8\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}$ was measured. A homogeneous linewidth of $25.3\ifmmode\pm\else\textpm\fi{}2.0\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ was obtained with or without an external magnetic field of about $14\phantom{\rule{0.3em}{0ex}}\mathrm{mT}$ . The fluorescence dynamics of the $^{1}D_{2}$ level obtained by a direct excitation in the $^{3}H_{4}\ensuremath{\rightarrow}^{1}D_{2}$ transition gives a nonexponential decay which indicates energy-transfer processes. This decay can be accurately fitted by the Inokuti-Hirayama model [J. Chem. Phys. 43, 1978 (1965)] with a radiative lifetime of $61\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ giving a minimal homogeneous linewidth of $2.6\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ . The spectral-hole lifetime due to population redistribution within the ground hyperfine levels is $16\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\mathrm{s}$. The results obtained for the ${\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}$ compound make this crystal an interesting host for quantum applications.Most of the experiments related to quantum information applications, involving rare-earth doped inorganic crystals, are performed on yttrium orthosilicate single crystals. The work presented here is motivated by the search of new compounds which can be used in the field of quantum computing and/or quantum storage. Relaxation times and hyperfine structure of the $^{3}H_{4}(0)\ensuremath{\rightarrow}^{1}D_{2}(0)$ transition in 1.4% ${\mathrm{Pr}}^{3+}:{\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}$ at $4\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ have been measured by photon-echo and spectral-hole-burning techniques. The hyperfine splittings of the ground $^{3}H_{4}(0)$ and the excited $^{1}D_{2}(0)$ states are $14.9\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $24.6\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ and $5.0\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $7.3\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, respectively. An inhomogeneous linewidth of $18.8\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}$ was measured. A homogeneous linewidth of $25.3\ifmmode\pm\else\textpm\fi{}2.0\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ was obtained with or without an external magnetic field of about $14\phantom{\rule{0.3em}{0ex}}\mathrm{mT}$. The fluorescence dynamics of the $^{1}D_{2}$ level obtained by a direct excitation in the $^{3}H_{4}\ensuremath{\rightarrow}^{1}D_{2}$ transition gives a nonexponential decay which indicates energy-transfer processes. This decay can be accurately fitted by the Inokuti-Hirayama model [J. Chem. Phys. 43, 1978 (1965)] with a radiative lifetime of $61\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ giving a minimal homogeneous linewidth of $2.6\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$. The spectral-hole lifetime due to population redistribution within the ground hyperfine levels is $16\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\mathrm{s}$. The results obtained for the ${\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}$ compound make this crystal an interesting host for quantum applications.

Physical Review BMay 15, 200719 citations

Spectroscopic study of hyperfine properties in Yb3+171:Y2SiO5

Alexey Tiranov, Antonio Ortu, Sacha Welinski +4 more

Rare-earth ion-doped crystals are promising systems for quantum communication and quantum information processing. In particular, paramagnetic rare-earth centers can be utilized to realize quantum coherent interfaces simultaneously for optical and microwave photons. In this paper, we study hyperfine and magnetic properties of a ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal doped with $^{171}\mathrm{Yb}^{3+}$ ions. This isotope is particularly interesting since it is the only rare--earth ion having electronic spin $S=\frac{1}{2}$ and nuclear spin $I=\frac{1}{2}$ , which results in the simplest possible hyperfine level structure. In this work, we determine the hyperfine tensors for the ground and excited states on the optical $^{2}\mathrm{F}_{7/2}(0)\ensuremath{\longleftrightarrow}^{2}\mathrm{F}_{5/2}(0)$ transition by combining spectral hole burning and optically detected magnetic resonance techniques. The resulting spin Hamiltonians correctly predict the magnetic-field dependence of all observed optical-hyperfine transitions, from zero applied field up to fields where the Zeeman interaction is dominating the hyperfine interaction. Using the optical absorption spectrum, we can also determine the order of the hyperfine levels in both states. These results pave the way for realizing solid-state optical and microwave quantum memories based on a $^{171}\mathrm{Yb}^{3+}:{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal.Rare-earth ion-doped crystals are promising systems for quantum communication and quantum information processing. In particular, paramagnetic rare-earth centers can be utilized to realize quantum coherent interfaces simultaneously for optical and microwave photons. In this paper, we study hyperfine and magnetic properties of a ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal doped with $^{171}\mathrm{Yb}^{3+}$ ions. This isotope is particularly interesting since it is the only rare--earth ion having electronic spin $S=\frac{1}{2}$ and nuclear spin $I=\frac{1}{2}$, which results in the simplest possible hyperfine level structure. In this work, we determine the hyperfine tensors for the ground and excited states on the optical $^{2}\mathrm{F}_{7/2}(0)\ensuremath{\longleftrightarrow}^{2}\mathrm{F}_{5/2}(0)$ transition by combining spectral hole burning and optically detected magnetic resonance techniques. The resulting spin Hamiltonians correctly predict the magnetic-field dependence of all observed optical-hyperfine transitions, from zero applied field up to fields where the Zeeman interaction is dominating the hyperfine interaction. Using the optical absorption spectrum, we can also determine the order of the hyperfine levels in both states. These results pave the way for realizing solid-state optical and microwave quantum memories based on a $^{171}\mathrm{Yb}^{3+}:{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal.

arXiv:1712.08616Physical review. B./Physical review. BNov 8, 201836 citations

Spectroscopic investigations of Eu 3+ :Y 2 SiO 5 for quantum memory applications

Björn Lauritzen, Nuala Timoney, Nicolas Gisin +5 more

Rare-earth-ion-doped solids are promising materials as light-matter interfaces for quantum applications. Europium doped into an yttrium orthosilicate crystal in particular has interesting coherence properties and a suitable ground-state energy-level structure for a quantum memory for light. In this paper we report on spectroscopic investigations of this material from the perspective of implementing an atomic frequency comb (AFC)-type quantum memory with spin-wave storage. For this goal we determine the order of the hyperfine levels in the ${}^{7}\phantom{\rule{-0.16em}{0ex}}{F}_{0}$ ground state and ${}^{5}\phantom{\rule{-0.16em}{0ex}}{D}_{0}$ excited state, and we measure the relative strengths of the optical transitions between these levels. We also apply spectral hole burning techniques in order to prepare the system as a well-defined $\ensuremath{\Lambda}$ system, as required for further quantum memory experiments. Furthermore, we measure the optical Rabi frequency on one of the strongest hyperfine transitions, a crucial experimental parameter for the AFC protocol. From this we also obtain a value for the transition dipole moment which is consistent with that obtained from absorption measurements.Rare-earth-ion-doped solids are promising materials as light-matter interfaces for quantum applications. Europium doped into an yttrium orthosilicate crystal in particular has interesting coherence properties and a suitable ground-state energy-level structure for a quantum memory for light. In this paper we report on spectroscopic investigations of this material from the perspective of implementing an atomic frequency comb (AFC)-type quantum memory with spin-wave storage. For this goal we determine the order of the hyperfine levels in the ${}^{7}\phantom{\rule{-0.16em}{0ex}}{F}_{0}$ ground state and ${}^{5}\phantom{\rule{-0.16em}{0ex}}{D}_{0}$ excited state, and we measure the relative strengths of the optical transitions between these levels. We also apply spectral hole burning techniques in order to prepare the system as a well-defined $\ensuremath{\Lambda}$ system, as required for further quantum memory experiments. Furthermore, we measure the optical Rabi frequency on one of the strongest hyperfine transitions, a crucial experimental parameter for the AFC protocol. From this we also obtain a value for the transition dipole moment which is consistent with that obtained from absorption measurements.

Physical Review BMar 14, 201280 citations

Concentration dependence of absorption and optical and hyperfine transition dynamics in Pr 3 + :La 2 (WO 4 ) 3

Florian Beaudoux, O. Guillot-Noël, Julien Lejay +2 more

Optical and hyperfine parameters of the 3H4–1D2 transition are investigated in Pr3 +:La2(WO4)3 for doping concentrations ranging from 0.02 to 3 at.%, at liquid helium temperatures. This includes optical inhomogeneous and homogeneous linewidths, peak absorption, excited-state population decays, spectral hole lifetime and inhomogeneous and homogeneous hyperfine linewidths. Optical inhomogeneous broadening with increasing Pr3 + concentration is limited due to close atomic radii between Pr3 + and La3 +. The peak absorption coefficient increases with increasing Pr3 + doping, reaching up to 28 cm−1. At the highest Pr3 + concentration, optical coherence lifetime is 4.6 μs and hole lifetime 2 s, which should allow one to transfer coherences and tailor the optical inhomogeneous linewidth, as required for rare earth-based optical quantum memories. Raman echo experiments show that hyperfine inhomogeneous linewidth and coherence lifetime (50 kHz and 250 μs respectively) are independent of Pr3 + concentration. These results suggest that highly doped crystals are useful for efficient and long-storage time quantum memories.Optical and hyperfine parameters of the 3H4–1D2 transition are investigated in Pr3 +:La2(WO4)3 for doping concentrations ranging from 0.02 to 3 at.%, at liquid helium temperatures. This includes optical inhomogeneous and homogeneous linewidths, peak absorption, excited-state population decays, spectral hole lifetime and inhomogeneous and homogeneous hyperfine linewidths. Optical inhomogeneous broadening with increasing Pr3 + concentration is limited due to close atomic radii between Pr3 + and La3 +. The peak absorption coefficient increases with increasing Pr3 + doping, reaching up to 28 cm−1. At the highest Pr3 + concentration, optical coherence lifetime is 4.6 μs and hole lifetime 2 s, which should allow one to transfer coherences and tailor the optical inhomogeneous linewidth, as required for rare earth-based optical quantum memories. Raman echo experiments show that hyperfine inhomogeneous linewidth and coherence lifetime (50 kHz and 250 μs respectively) are independent of Pr3 + concentration. These results suggest that highly doped crystals are useful for efficient and long-storage time quantum memories.

Journal of Physics B Atomic Molecular and Optical PhysicsJun 8, 20128 citations

High-resolution spectroscopy and novel crystal-field methods for rare-earth based quantum information processing

Sebastian P. Horvath

Rare-earth doped insulators have been widely recognized as excellent candidate materials for optical quantum computing and information processing. This is principally due to a combination of optical coherence times of up to milliseconds and ground-state hyperfine coherence times of seconds exhibited by rare-earth 4𝑓 𝑁 states. A key contender among rare-earth doped materials is Er3+:Y2SiO5, for which homogeneous linewidths as narrow as 50 Hz have been reported, and for which transitions between the ground and first excited states fall within the 1.5 𝜇m telecommunications wavelength band. However, attempts to utilize this material for spin-wave storage have been hampered by the complexity of the excited-state hyperfine structure, which inhibits the necessary theoretical work required to predict the location of zero first-order zeeman transitions. To address this, a novel crystal-field fitting method was developed to allow an accurate analysis of the 𝐶1 point-group symmetry sites of Y2SiO5. This work was complemented with spectral hole-burning spectroscopy, which revealed ground-state hyperfine level storage with a lifetime of 1.6 ± 0.4 seconds for the 4I15/2𝑍1 → 4F9/2𝐷1 transition. This type of storage time is uncharacteristic for erbium without an external magnetic field, since spin-flips of the unpaired electron in nearby Er3+ ions are typically understood to lead to fast hole filling. The development process of the theoretical and experimental tools required to perform the above work enabled several additional investigations. In particular, the novel crystal-field fitting methods were applied to the 𝑆4 site of Ce3+:LiYF4 and to the 𝐶2𝑣 site of Sm3+:Na+/Li+:CaF2/SrF2. These studies consisted of excellent tests for the developed methods yet also amounted to interesting investigations in their own respect. Similarly, the experimental work afforded an opportunity to directly determine the hyperfine splittings of the 5I8𝑍1 → 5F5𝐷1 transition in Ho3+:KY3F10. This was achieved using high-resolution excitation spectroscopy. Furthermore, the experimentally determined hyperfine structure could be accurately reproduced using a crystal field model. Finally, a lifetime measurement of the 6H7/2 state of Sm3+:LiYF4 was conducted. By utilizing an infrared free-electron laser, pico-second pump-probe spectroscopy allowed for a direct measurements of one of the shortest lifetimes of an RE3+ doped insulator reported in the literature to date. This confirmed the previously suggested two-gradient modification required for the energy-gap law at very short time scales.Rare-earth doped insulators have been widely recognized as excellent candidate materials for optical quantum computing and information processing. This is principally due to a combination of optical coherence times of up to milliseconds and ground-state hyperfine coherence times of seconds exhibited by rare-earth 4𝑓 𝑁 states. A key contender among rare-earth doped materials is Er3+:Y2SiO5, for which homogeneous linewidths as narrow as 50 Hz have been reported, and for which transitions between the ground and first excited states fall within the 1.5 𝜇m telecommunications wavelength band. However, attempts to utilize this material for spin-wave storage have been hampered by the complexity of the excited-state hyperfine structure, which inhibits the necessary theoretical work required to predict the location of zero first-order zeeman transitions. To address this, a novel crystal-field fitting method was developed to allow an accurate analysis of the 𝐶1 point-group symmetry sites of Y2SiO5. This work was complemented with spectral hole-burning spectroscopy, which revealed ground-state hyperfine level storage with a lifetime of 1.6 ± 0.4 seconds for the 4I15/2𝑍1 → 4F9/2𝐷1 transition. This type of storage time is uncharacteristic for erbium without an external magnetic field, since spin-flips of the unpaired electron in nearby Er3+ ions are typically understood to lead to fast hole filling. The development process of the theoretical and experimental tools required to perform the above work enabled several additional investigations. In particular, the novel crystal-field fitting methods were applied to the 𝑆4 site of Ce3+:LiYF4 and to the 𝐶2𝑣 site of Sm3+:Na+/Li+:CaF2/SrF2. These studies consisted of excellent tests for the developed methods yet also amounted to interesting investigations in their own respect. Similarly, the experimental work afforded an opportunity to directly determine the hyperfine splittings of the 5I8𝑍1 → 5F5𝐷1 transition in Ho3+:KY3F10. This was achieved using high-resolution excitation spectroscopy. Furthermore, the experimentally determined hyperfine structure could be accurately reproduced using a crystal field model. Finally, a lifetime measurement of the 6H7/2 state of Sm3+:LiYF4 was conducted. By utilizing an infrared free-electron laser, pico-second pump-probe spectroscopy allowed for a direct measurements of one of the shortest lifetimes of an RE3+ doped insulator reported in the literature to date. This confirmed the previously suggested two-gradient modification required for the energy-gap law at very short time scales.

Jan 1, 20167 citations

Rare-earth ions doped into low nuclear-spin density host crystals provide a promising platform for quantum information storage and processing. Calcium tungstate

({\mathrm{CaWO}}_{4})

(^{141}\mathrm{Pr}^{3+})

doped in

{\mathrm{CaWO}}_{4}

at liquid-helium temperatures. The hyperfine structures of the

{}^{3}{H}_{4}

(0) and

{}^{1}{D}_{2}

(0) states are determined by spectral hole burning. The results indicate that

{\mathrm{Pr}}^{3+}

{\mathrm{CaWO}}_{4}

is an appealing candidate for quantum memory in quantum information processing.

{\mathrm{Pr}}^{3+}:{\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}

4\phantom{\rule{0.3em}{0ex}}\mathrm{K}

have been measured by photon-echo and spectral-hole-burning techniques. The hyperfine splittings of the ground

^{3}H_{4}(0)

and the excited

^{1}D_{2}(0)

states are $14.9\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $24.6\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ and $5.0\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, $7.3\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, respectively. An inhomogeneous linewidth of $18.8\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}$ was measured. A homogeneous linewidth of $25.3\ifmmode\pm\else\textpm\fi{}2.0\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ was obtained with or without an external magnetic field of about

14\phantom{\rule{0.3em}{0ex}}\mathrm{mT}

. The fluorescence dynamics of the

^{1}D_{2}

level obtained by a direct excitation in the $^{3}H_{4}\ensuremath{\rightarrow}^{1}D_{2}$ transition gives a nonexponential decay which indicates energy-transfer processes. This decay can be accurately fitted by the Inokuti-Hirayama model [J. Chem. Phys. 43, 1978 (1965)] with a radiative lifetime of $61\ifmmode\pm\else\textpm\fi{}1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ giving a minimal homogeneous linewidth of

2.6\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}

. The spectral-hole lifetime due to population redistribution within the ground hyperfine levels is $16\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\mathrm{s}$. The results obtained for the

{\mathrm{La}}_{2}{(\mathrm{W}{\mathrm{O}}_{4})}_{3}

compound make this crystal an interesting host for quantum applications.

{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}

crystal doped with

^{171}\mathrm{Yb}^{3+}

ions. This isotope is particularly interesting since it is the only rare--earth ion having electronic spin

S=\frac{1}{2}

and nuclear spin

I=\frac{1}{2}

, which results in the simplest possible hyperfine level structure. In this work, we determine the hyperfine tensors for the ground and excited states on the optical $^{2}\mathrm{F}_{7/2}(0)\ensuremath{\longleftrightarrow}^{2}\mathrm{F}_{5/2}(0)$ transition by combining spectral hole burning and optically detected magnetic resonance techniques. The resulting spin Hamiltonians correctly predict the magnetic-field dependence of all observed optical-hyperfine transitions, from zero applied field up to fields where the Zeeman interaction is dominating the hyperfine interaction. Using the optical absorption spectrum, we can also determine the order of the hyperfine levels in both states. These results pave the way for realizing solid-state optical and microwave quantum memories based on a

^{171}\mathrm{Yb}^{3+}:{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}

crystal.

{}^{7}\phantom{\rule{-0.16em}{0ex}}{F}_{0}

ground state and

{}^{5}\phantom{\rule{-0.16em}{0ex}}{D}_{0}

excited state, and we measure the relative strengths of the optical transitions between these levels. We also apply spectral hole burning techniques in order to prepare the system as a well-defined $\ensuremath{\Lambda}$ system, as required for further quantum memory experiments. Furthermore, we measure the optical Rabi frequency on one of the strongest hyperfine transitions, a crucial experimental parameter for the AFC protocol. From this we also obtain a value for the transition dipole moment which is consistent with that obtained from absorption measurements.