arXiv:1606.06937 · Physical review. B./Physical review. B

High-resolution optical spectroscopy and magnetic properties of Yb 3 + in Y 2 SiO 5

Sacha Welinski, Alban Ferrier, Mikael Afzelius, Philippe Goldner

Published Oct 10, 2016• 46 citations

Abstract

Rare-earth doped crystals are promising systems for quantum information processing. In particular, paramagnetic rare earths could be used to build coherent interfaces with optical and microwave photons. In addition, isotopes with nonzero nuclear spins could provide long-lived states for quantum state storage and processing. ${\mathrm{Yb}}^{3+}$ is particularly interesting in this respect since it is the only paramagnetic rare earth with a spin-$\frac{1}{2}$ isotope, which corresponds to the simplest possible level structure. In this paper, we report on the optical and magnetic properties of ${\mathrm{Yb}}^{3+}$ in the two sites of ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$, a commonly used crystal for quantum applications. We measured optical inhomogeneous linewidths, peak absorption coefficients, oscillator strengths, and excited-state lifetimes. The Zeeman tensors were also determined in the ground and excited states, as well as the ground-state hyperfine tensor for the $^{171}\mathrm{Yb}^{3+}$ ($I=\frac{1}{2}$) isotope. These results suggest that ${\mathrm{Yb}}^{3+}$:${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ is a promising material for applications like solid-state optical and microwave quantum memories.

DOI: 10.1103/physrevb.94.155116

Related papers

Spectroscopic study of hyperfine properties in Yb3+171:Y2SiO5

Alexey Tiranov, Antonio Ortu, Sacha Welinski +4 more

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

Optical coherence and spin population dynamics in $^{171}$Yb$^{3+}$:Y$_2$SiO$_5$ single crystals

F. Chiossi, Eloïse Lafitte-Houssat, Alban Ferrier +6 more

arXiv:2312.00579Dec 1, 20230 citations

Investigation of the Electronic Structure and Optical, EPR, and ODMR Spectroscopic Properties for 171Yb3+-Doped Y2SiO5 Crystal: A Combined Theoretical Approach

Xiaonan Zhou, Hong-Gang Liu, Z. Y. He +2 more

Inorganic ChemistryAug 31, 202023 citations

Characterization of Yb 3 + 171 : YVO 4 for photonic quantum technologies

Jonathan M. Kindem, John G. Bartholomew, Philip J. T. Woodburn +5 more

arXiv:1805.01068Physical review. B./Physical review. BJul 5, 201859 citations

Optical decoherence, spectroscopy, and magnetic g tensors for the 1.5-µm I 15 / 2 4 − I 13 / 2 4 transitions of E r 3 + dopants at the C 2 -symmetry site in Y 2 O 3

Thomas Böttger, Todd L. Harris, G. D. Reinemer +2 more

Physical review. B./Physical review. BJul 17, 20248 citations

Optical spectroscopy, magnetic g tensors, and decoherence studies of magnetic dipole transitions of E r 3 + at C 3 i -symmetry lattice sites in Y 2 O 3 at 1.5 µm

Thomas Böttger, G. D. Reinemer, Charles W. Thiel +1 more

Physical review. B./Physical review. BJan 7, 20253 citations

arXiv:1606.06937 · Physical review. B./Physical review. B

High-resolution optical spectroscopy and magnetic properties of Yb 3 + in Y 2 SiO 5

Sacha Welinski, Alban Ferrier, Mikael Afzelius, Philippe Goldner

Published Oct 10, 2016• 46 citations

arXiv HTML PDF

Abstract

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

is particularly interesting in this respect since it is the only paramagnetic rare earth with a spin-

\frac{1}{2}

isotope, which corresponds to the simplest possible level structure. In this paper, we report on the optical and magnetic properties of

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

in the two sites of

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

, a commonly used crystal for quantum applications. We measured optical inhomogeneous linewidths, peak absorption coefficients, oscillator strengths, and excited-state lifetimes. The Zeeman tensors were also determined in the ground and excited states, as well as the ground-state hyperfine tensor for the

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

(

I=\frac{1}{2}

) isotope. These results suggest that

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

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

is a promising material for applications like solid-state optical and microwave quantum memories.

DOI: 10.1103/physrevb.94.155116

Related papers

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

Optical coherence and spin population dynamics in $^{171}$ Yb $^{3+}$ :Y $_2$ SiO $_5$ single crystalsOptical coherence and spin population dynamics in $^{171}$Yb$^{3+}$:Y$_2$SiO$_5$ single crystals

F. Chiossi, Eloïse Lafitte-Houssat, Alban Ferrier +6 more

$^{171}$ Yb $^{3+}$ -doped Y $_2$ SiO $_5$ crystals are a promising platform for optical quantum memories in long-distance quantum communications. The relevance of this material lies in $^{171}$ Yb long optical and spin coherence times, along with a large hyperfine splitting, enabling long quantum storage over large bandwidths. Mechanisms affecting the optical decoherence are however not precisely known, especially since low-temperature measurements have so far focused on the 2 to 4 K range. In this work, we performed two- and three-pulse photon echoes and spectral hole burning to determine optical homogeneous linewidths in two 171 Yb:YSO crystals doped at 2 and 10 ppm. Experiments were performed in the 40 mK to 18 K temperature range, leading to linewidths between 320 Hz, among the narrowest reported for rare-earth ions, and several MHz. Our results show that above 6 K the homogeneous linewidth is mainly due to an elastic two-phonon process which results in a slow broadening with temperature, the homogeneous linewidth reaching only 25 kHz at 10 K. At lower temperatures, interactions with $^{89}$ Yb nuclear spin-flips, paramagnetic defects or impurities, and also Yb-Yb interactions for the higher concentrated crystal, are likely the main limiting factor to the homogeneous linewidth. In particular, we conclude that the direct effect of spin and optical excited state lifetime is a minor contribution to optical decoherence in the whole temperature range studied. Our results indicate possible paths and regimes for further decreasing the homogeneous linewidths or maintaining narrow lines at higher $^{171}$ Yb concentration.$^{171}$Yb$^{3+}$-doped Y$_2$SiO$_5$ crystals are a promising platform for optical quantum memories in long-distance quantum communications. The relevance of this material lies in $^{171}$Yb long optical and spin coherence times, along with a large hyperfine splitting, enabling long quantum storage over large bandwidths. Mechanisms affecting the optical decoherence are however not precisely known, especially since low-temperature measurements have so far focused on the 2 to 4 K range. In this work, we performed two- and three-pulse photon echoes and spectral hole burning to determine optical homogeneous linewidths in two 171 Yb:YSO crystals doped at 2 and 10 ppm. Experiments were performed in the 40 mK to 18 K temperature range, leading to linewidths between 320 Hz, among the narrowest reported for rare-earth ions, and several MHz. Our results show that above 6 K the homogeneous linewidth is mainly due to an elastic two-phonon process which results in a slow broadening with temperature, the homogeneous linewidth reaching only 25 kHz at 10 K. At lower temperatures, interactions with $^{89}$Yb nuclear spin-flips, paramagnetic defects or impurities, and also Yb-Yb interactions for the higher concentrated crystal, are likely the main limiting factor to the homogeneous linewidth. In particular, we conclude that the direct effect of spin and optical excited state lifetime is a minor contribution to optical decoherence in the whole temperature range studied. Our results indicate possible paths and regimes for further decreasing the homogeneous linewidths or maintaining narrow lines at higher $^{171}$Yb concentration.

arXiv:2312.00579Dec 1, 20230 citations

Investigation of the Electronic Structure and Optical, EPR, and ODMR Spectroscopic Properties for 171Yb3+-Doped Y2SiO5 Crystal: A Combined Theoretical Approach

Xiaonan Zhou, Hong-Gang Liu, Z. Y. He +2 more

Various spectroscopic properties of Yb 3+ -doped Y 2 SiO 5 crystal have been extensively investigated due to its promising application in quantum information processing. However, the local structure, electronic structure of Yb 3+:Y 2 SiO 5 crystal, and its optical and magnetic properties have not been comprehensively studied from a theoretical viewpoint. In this work, the geometric and electronic structures of Yb 3+ that replaces two crystallographic Y 3+ sites in the Y 2 SiO 5 crystal are first obtained by the method of density functional theory (DFT). Then, the optical, electron paramagnetic resonance (EPR), and optically detected magnetic resonance (ODMR) spectra for 171 Yb 3+ (nuclear spin I = 1/2) at such two sites are simultaneously calculated in the framework of the complete diagonalization (of energy) matrix (CDM) based on the optimized local structure around 171 Yb 3+ ion by DFT. The various calculated spectroscopic properties by such combined theoretical approach are consistent with the experimental ones, which demonstrates that CDM is effective and particularly suitable for calculating hyperfine A -tensors under zero, low, and intermediate magnetic field. More importantly, based on the obtained accurate hyperfine structure of 171 Yb 3+ in Y 2 SiO 5 crystal, the possible “clock transitions”, which can enhance the optical coherence time, can be assigned or predicted by the present approach. This study successfully explains the spectroscopic properties of 171 Yb 3+ -doped Y 2 SiO 5 and provides a feasible method to design and search for practical rare-earth-doped quantum information materials for the community.Various spectroscopic properties of Yb 3+ -doped Y 2 SiO 5 crystal have been extensively investigated due to its promising application in quantum information processing. However, the local structure, electronic structure of Yb 3+:Y 2 SiO 5 crystal, and its optical and magnetic properties have not been comprehensively studied from a theoretical viewpoint. In this work, the geometric and electronic structures of Yb 3+ that replaces two crystallographic Y 3+ sites in the Y 2 SiO 5 crystal are first obtained by the method of density functional theory (DFT). Then, the optical, electron paramagnetic resonance (EPR), and optically detected magnetic resonance (ODMR) spectra for 171 Yb 3+ (nuclear spin I = 1/2) at such two sites are simultaneously calculated in the framework of the complete diagonalization (of energy) matrix (CDM) based on the optimized local structure around 171 Yb 3+ ion by DFT. The various calculated spectroscopic properties by such combined theoretical approach are consistent with the experimental ones, which demonstrates that CDM is effective and particularly suitable for calculating hyperfine A -tensors under zero, low, and intermediate magnetic field. More importantly, based on the obtained accurate hyperfine structure of 171 Yb 3+ in Y 2 SiO 5 crystal, the possible “clock transitions”, which can enhance the optical coherence time, can be assigned or predicted by the present approach. This study successfully explains the spectroscopic properties of 171 Yb 3+ -doped Y 2 SiO 5 and provides a feasible method to design and search for practical rare-earth-doped quantum information materials for the community.

Inorganic ChemistryAug 31, 202023 citations

Characterization of Yb 3 + 171 : YVO 4 for photonic quantum technologies

Jonathan M. Kindem, John G. Bartholomew, Philip J. T. Woodburn +5 more

Rare-earth ion crystals are a promising platform for implementing solid-state quantum interfaces, yet there are few combinations of rare-earth and host crystals that simultaneously deliver large optical absorption, narrow inhomogeneous linewidths, and long coherence times. This work investigates the optical and spin properties of ${}^{171}$ Yb ${}^{3+}$ ions in YVO ${}_{4}$ . The observed properties and simple energy-level structure of the ${}^{171}$ Yb ${}^{3+}$ ion show that this material has significant potential for creating efficient quantum interfaces, such as ensemble-based memories, microwave-to-optical transducers, and optically addressable single rare-earth ion spin qubits.Rare-earth ion crystals are a promising platform for implementing solid-state quantum interfaces, yet there are few combinations of rare-earth and host crystals that simultaneously deliver large optical absorption, narrow inhomogeneous linewidths, and long coherence times. This work investigates the optical and spin properties of ${}^{171}$Yb${}^{3+}$ ions in YVO${}_{4}$. The observed properties and simple energy-level structure of the ${}^{171}$Yb${}^{3+}$ ion show that this material has significant potential for creating efficient quantum interfaces, such as ensemble-based memories, microwave-to-optical transducers, and optically addressable single rare-earth ion spin qubits.

arXiv:1805.01068Physical review. B./Physical review. BJul 5, 201859 citations

Optical decoherence, spectroscopy, and magnetic g tensors for the 1.5-µm I 15 / 2 4 − I 13 / 2 4 transitions of E r 3 + dopants at the C 2 -symmetry site in Y 2 O 3

Thomas Böttger, Todd L. Harris, G. D. Reinemer +2 more

Erbium-doped solids are a promising platform for quantum technology due to the $\mathrm{E}{\mathrm{r}}^{3+}$ 1.5-\textmu{}m optical transition in the telecom C band that can offer long coherence times. To characterize the intrinsic ${\mathrm{C}}_{2}$ site of $\mathrm{E}{\mathrm{r}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ for quantum information and photonic signal-processing applications, absorption and site-selective fluorescence spectroscopy were used to assign the $\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}$ $\ensuremath{\leftrightarrow}$ $^{4}I_{13/2}$ transitions. The lowest-to-lowest transition occurs at 1535.608 nm and laser absorption determined an inhomogeneous linewidth of 780 MHz in a 0.005%-doped crystal at 3.4 K. Time-resolved fluorescence established an upper limit for the excited-state lifetime of 8.5 ms. Angular-dependent Zeeman absorption was used to determine ground- and excited-state $g$ tensors. The ${\mathrm{C}}_{2}$ -site $g$ tensor components for the ground state are ${g}_{x}=1.60$ , ${g}_{y}=4.71$ , and ${g}_{z}=11.93$ with a tipping angle of \ensuremath{\alpha} = $2.{06}^{\ensuremath{\circ}}$, whereas for the excited state the components are ${g}_{x}=1.08$ , ${g}_{y}=4.36$ , and ${g}_{z}=10.07$ with a tipping angle of \ensuremath{\alpha} = $\ensuremath{-}11.{7}^{\ensuremath{\circ}}$. Optical decoherence can be suppressed by the application of a magnetic field parallel to $\ensuremath{\langle}111\ensuremath{\rangle}$ crystal axes where all ${\mathrm{C}}_{2}$ sites become nearly magnetically equivalent with large $g$ values so that spin flips of neighboring $\mathrm{E}{\mathrm{r}}^{3+}$ ions can be simultaneously suppressed. Using this magnetic field direction, two-pulse photon echoes gave a homogeneous linewidth of 5 kHz for an applied magnetic field of 0.5 T, narrowing and saturating at 2.5 kHz at 3.5 T. Decoherence over intermediate magnetic fields was described by spectral diffusion due to $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic dipole interactions driven by the direct phonon process. With $\mathrm{E}{\mathrm{r}}^{3+}$ : ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ absorption at a convenient telecom laser wavelength and the ability to fabricate waveguides, our study suggests that this is a promising material system for quantum information and spectral hole-burning signal-processing applications.Erbium-doped solids are a promising platform for quantum technology due to the $\mathrm{E}{\mathrm{r}}^{3+}$ 1.5-\textmu{}m optical transition in the telecom C band that can offer long coherence times. To characterize the intrinsic ${\mathrm{C}}_{2}$ site of $\mathrm{E}{\mathrm{r}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ for quantum information and photonic signal-processing applications, absorption and site-selective fluorescence spectroscopy were used to assign the $\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}$$\ensuremath{\leftrightarrow}$$^{4}I_{13/2}$ transitions. The lowest-to-lowest transition occurs at 1535.608 nm and laser absorption determined an inhomogeneous linewidth of 780 MHz in a 0.005%-doped crystal at 3.4 K. Time-resolved fluorescence established an upper limit for the excited-state lifetime of 8.5 ms. Angular-dependent Zeeman absorption was used to determine ground- and excited-state $g$ tensors. The ${\mathrm{C}}_{2}$-site $g$ tensor components for the ground state are ${g}_{x}=1.60$, ${g}_{y}=4.71$, and ${g}_{z}=11.93$ with a tipping angle of \ensuremath{\alpha} = $2.{06}^{\ensuremath{\circ}}$, whereas for the excited state the components are ${g}_{x}=1.08$, ${g}_{y}=4.36$, and ${g}_{z}=10.07$ with a tipping angle of \ensuremath{\alpha} = $\ensuremath{-}11.{7}^{\ensuremath{\circ}}$. Optical decoherence can be suppressed by the application of a magnetic field parallel to $\ensuremath{\langle}111\ensuremath{\rangle}$ crystal axes where all ${\mathrm{C}}_{2}$ sites become nearly magnetically equivalent with large $g$ values so that spin flips of neighboring $\mathrm{E}{\mathrm{r}}^{3+}$ ions can be simultaneously suppressed. Using this magnetic field direction, two-pulse photon echoes gave a homogeneous linewidth of 5 kHz for an applied magnetic field of 0.5 T, narrowing and saturating at 2.5 kHz at 3.5 T. Decoherence over intermediate magnetic fields was described by spectral diffusion due to $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic dipole interactions driven by the direct phonon process. With $\mathrm{E}{\mathrm{r}}^{3+}$:${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ absorption at a convenient telecom laser wavelength and the ability to fabricate waveguides, our study suggests that this is a promising material system for quantum information and spectral hole-burning signal-processing applications.

Physical review. B./Physical review. BJul 17, 20248 citations

Optical spectroscopy, magnetic g tensors, and decoherence studies of magnetic dipole transitions of E r 3 + at C 3 i -symmetry lattice sites in Y 2 O 3 at 1.5 µm

Thomas Böttger, G. D. Reinemer, Charles W. Thiel +1 more

When introduced as dopants into ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ , $\mathrm{E}{\mathrm{r}}^{3+}$ ions replace ${\mathrm{Y}}^{3+}$ ions at two crystallographic sites of ${\mathrm{C}}_{2}$ and ${\mathrm{C}}_{3\mathrm{i}}$ point symmetries. The ${\mathrm{C}}_{3\mathrm{i}}$ site is particularly interesting, given that the inversion symmetry prohibits static electric-dipole moments and electric-dipole transitions, resulting in 1.5 \textmu{}m optical transitions characterized by purely magnetic-dipole properties. Employing $\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}\ensuremath{\leftrightarrow}^{4}I_{13/2}$ transitions, we examined the inherent ${\mathrm{C}}_{3\mathrm{i}}$ site of $\mathrm{E}{\mathrm{r}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ for its potential in quantum information science and spectral hole burning applications. Our approach involved absorption and site-selective fluorescence spectroscopy to discern $\mathrm{E}{\mathrm{r}}^{3+}$ energy levels and revealed an excited-state lifetime of 14.6 ms. High-resolution laser spectroscopy at 3.7 K indicated an inhomogeneous linewidth of 1.3 GHz in our sample. Orientation-dependent Zeeman laser absorption spectroscopy facilitated the determination of the full $g$ tensors for both the ground and excited states, confirming the ${\mathrm{C}}_{3\mathrm{i}}$ site assignment. Furthermore, it identified a suitable magnetic field direction for mitigating decoherence, a finding corroborated through two-pulse photon echo spectroscopy. Our study presents photon echo coherent transient measurements related to magnetic-dipole-allowed rare-earth ion transitions at the ${\mathrm{C}}_{3\mathrm{i}}$ site. The observed decoherence, attributed to spectral diffusion arising from $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic-dipole interactions, underscores the complex spin dynamics at play in systems with multiple inequivalent dopant sites. Coupled with the practicality of telecom laser wavelengths, our investigation highlights the promise of magnetic-dipole transitions in advancing quantum information science and spectral hole burning applications.When introduced as dopants into ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$, $\mathrm{E}{\mathrm{r}}^{3+}$ ions replace ${\mathrm{Y}}^{3+}$ ions at two crystallographic sites of ${\mathrm{C}}_{2}$ and ${\mathrm{C}}_{3\mathrm{i}}$ point symmetries. The ${\mathrm{C}}_{3\mathrm{i}}$ site is particularly interesting, given that the inversion symmetry prohibits static electric-dipole moments and electric-dipole transitions, resulting in 1.5 \textmu{}m optical transitions characterized by purely magnetic-dipole properties. Employing $\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}\ensuremath{\leftrightarrow}^{4}I_{13/2}$ transitions, we examined the inherent ${\mathrm{C}}_{3\mathrm{i}}$ site of $\mathrm{E}{\mathrm{r}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ for its potential in quantum information science and spectral hole burning applications. Our approach involved absorption and site-selective fluorescence spectroscopy to discern $\mathrm{E}{\mathrm{r}}^{3+}$ energy levels and revealed an excited-state lifetime of 14.6 ms. High-resolution laser spectroscopy at 3.7 K indicated an inhomogeneous linewidth of 1.3 GHz in our sample. Orientation-dependent Zeeman laser absorption spectroscopy facilitated the determination of the full $g$ tensors for both the ground and excited states, confirming the ${\mathrm{C}}_{3\mathrm{i}}$ site assignment. Furthermore, it identified a suitable magnetic field direction for mitigating decoherence, a finding corroborated through two-pulse photon echo spectroscopy. Our study presents photon echo coherent transient measurements related to magnetic-dipole-allowed rare-earth ion transitions at the ${\mathrm{C}}_{3\mathrm{i}}$ site. The observed decoherence, attributed to spectral diffusion arising from $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic-dipole interactions, underscores the complex spin dynamics at play in systems with multiple inequivalent dopant sites. Coupled with the practicality of telecom laser wavelengths, our investigation highlights the promise of magnetic-dipole transitions in advancing quantum information science and spectral hole burning applications.

Physical review. B./Physical review. BJan 7, 20253 citations

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

is particularly interesting in this respect since it is the only paramagnetic rare earth with a spin-

\frac{1}{2}

isotope, which corresponds to the simplest possible level structure. In this paper, we report on the optical and magnetic properties of

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

in the two sites of

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

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

(

I=\frac{1}{2}

) isotope. These results suggest that

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

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

is a promising material for applications like solid-state optical and microwave quantum memories.

{\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.

Optical coherence and spin population dynamics in

^{171}

^{3+}

_2

SiO

_5

single crystals

^{171}

^{3+}

-doped Y

_2

SiO

_5

crystals are a promising platform for optical quantum memories in long-distance quantum communications. The relevance of this material lies in

^{171}

Yb long optical and spin coherence times, along with a large hyperfine splitting, enabling long quantum storage over large bandwidths. Mechanisms affecting the optical decoherence are however not precisely known, especially since low-temperature measurements have so far focused on the 2 to 4 K range. In this work, we performed two- and three-pulse photon echoes and spectral hole burning to determine optical homogeneous linewidths in two 171 Yb:YSO crystals doped at 2 and 10 ppm. Experiments were performed in the 40 mK to 18 K temperature range, leading to linewidths between 320 Hz, among the narrowest reported for rare-earth ions, and several MHz. Our results show that above 6 K the homogeneous linewidth is mainly due to an elastic two-phonon process which results in a slow broadening with temperature, the homogeneous linewidth reaching only 25 kHz at 10 K. At lower temperatures, interactions with

^{89}

Yb nuclear spin-flips, paramagnetic defects or impurities, and also Yb-Yb interactions for the higher concentrated crystal, are likely the main limiting factor to the homogeneous linewidth. In particular, we conclude that the direct effect of spin and optical excited state lifetime is a minor contribution to optical decoherence in the whole temperature range studied. Our results indicate possible paths and regimes for further decreasing the homogeneous linewidths or maintaining narrow lines at higher

^{171}

Yb concentration.

{}^{171}

{}^{3+}

ions in YVO

{}_{4}

. The observed properties and simple energy-level structure of the

{}^{171}

{}^{3+}

ion show that this material has significant potential for creating efficient quantum interfaces, such as ensemble-based memories, microwave-to-optical transducers, and optically addressable single rare-earth ion spin qubits.

Erbium-doped solids are a promising platform for quantum technology due to the

\mathrm{E}{\mathrm{r}}^{3+}

1.5-\textmu{}m optical transition in the telecom C band that can offer long coherence times. To characterize the intrinsic

{\mathrm{C}}_{2}

site of

\mathrm{E}{\mathrm{r}}^{3+}

{\mathrm{Y}}_{2}{\mathrm{O}}_{3}

for quantum information and photonic signal-processing applications, absorption and site-selective fluorescence spectroscopy were used to assign the

\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}

$\ensuremath{\leftrightarrow}$

^{4}I_{13/2}

transitions. The lowest-to-lowest transition occurs at 1535.608 nm and laser absorption determined an inhomogeneous linewidth of 780 MHz in a 0.005%-doped crystal at 3.4 K. Time-resolved fluorescence established an upper limit for the excited-state lifetime of 8.5 ms. Angular-dependent Zeeman absorption was used to determine ground- and excited-state

g

tensors. The

{\mathrm{C}}_{2}

-site

g

tensor components for the ground state are

{g}_{x}=1.60

{g}_{y}=4.71

, and

{g}_{z}=11.93

with a tipping angle of \ensuremath{\alpha} = $2.{06}^{\ensuremath{\circ}}$, whereas for the excited state the components are

{g}_{x}=1.08

{g}_{y}=4.36

, and

{g}_{z}=10.07

with a tipping angle of \ensuremath{\alpha} = $\ensuremath{-}11.{7}^{\ensuremath{\circ}}$. Optical decoherence can be suppressed by the application of a magnetic field parallel to $\ensuremath{\langle}111\ensuremath{\rangle}$ crystal axes where all

{\mathrm{C}}_{2}

sites become nearly magnetically equivalent with large

g

values so that spin flips of neighboring

\mathrm{E}{\mathrm{r}}^{3+}

ions can be simultaneously suppressed. Using this magnetic field direction, two-pulse photon echoes gave a homogeneous linewidth of 5 kHz for an applied magnetic field of 0.5 T, narrowing and saturating at 2.5 kHz at 3.5 T. Decoherence over intermediate magnetic fields was described by spectral diffusion due to $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic dipole interactions driven by the direct phonon process. With

\mathrm{E}{\mathrm{r}}^{3+}

{\mathrm{Y}}_{2}{\mathrm{O}}_{3}

absorption at a convenient telecom laser wavelength and the ability to fabricate waveguides, our study suggests that this is a promising material system for quantum information and spectral hole-burning signal-processing applications.

When introduced as dopants into

{\mathrm{Y}}_{2}{\mathrm{O}}_{3}

\mathrm{E}{\mathrm{r}}^{3+}

ions replace

{\mathrm{Y}}^{3+}

ions at two crystallographic sites of

{\mathrm{C}}_{2}

and

{\mathrm{C}}_{3\mathrm{i}}

point symmetries. The

{\mathrm{C}}_{3\mathrm{i}}

site is particularly interesting, given that the inversion symmetry prohibits static electric-dipole moments and electric-dipole transitions, resulting in 1.5 \textmu{}m optical transitions characterized by purely magnetic-dipole properties. Employing $\mathrm{E}{\mathrm{r}}^{3+}\phantom{\rule{4pt}{0ex}}^{4}I_{15/2}\ensuremath{\leftrightarrow}^{4}I_{13/2}$ transitions, we examined the inherent

{\mathrm{C}}_{3\mathrm{i}}

site of

\mathrm{E}{\mathrm{r}}^{3+}

{\mathrm{Y}}_{2}{\mathrm{O}}_{3}

for its potential in quantum information science and spectral hole burning applications. Our approach involved absorption and site-selective fluorescence spectroscopy to discern

\mathrm{E}{\mathrm{r}}^{3+}

energy levels and revealed an excited-state lifetime of 14.6 ms. High-resolution laser spectroscopy at 3.7 K indicated an inhomogeneous linewidth of 1.3 GHz in our sample. Orientation-dependent Zeeman laser absorption spectroscopy facilitated the determination of the full

g

tensors for both the ground and excited states, confirming the

{\mathrm{C}}_{3\mathrm{i}}

site assignment. Furthermore, it identified a suitable magnetic field direction for mitigating decoherence, a finding corroborated through two-pulse photon echo spectroscopy. Our study presents photon echo coherent transient measurements related to magnetic-dipole-allowed rare-earth ion transitions at the

{\mathrm{C}}_{3\mathrm{i}}

site. The observed decoherence, attributed to spectral diffusion arising from $\mathrm{E}{\mathrm{r}}^{3+}\text{\ensuremath{-}}\mathrm{E}{\mathrm{r}}^{3+}$ magnetic-dipole interactions, underscores the complex spin dynamics at play in systems with multiple inequivalent dopant sites. Coupled with the practicality of telecom laser wavelengths, our investigation highlights the promise of magnetic-dipole transitions in advancing quantum information science and spectral hole burning applications.