Physical Review B

Spectral hole-burning spectroscopy in Nd 3 + : Y V O 4

Sara R. Hastings-Simon, Mikael Afzelius, Jiří Minář, M. U. Staudt, Björn Lauritzen, Hugues de Riedmatten, Nicolas Gisin, A. Amari, Andreas Walther, Stefan Kröll, Enrico Cavalli, Marco Bettinelli

Published Mar 10, 2008• 41 citations

Publisher

Abstract

We present spectral hole-burning measurements on the $879\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, $^{4}I_{9∕2}\ensuremath{\rightarrow}^{4}F_{3∕2}$ transition in ${\mathrm{Nd}}^{3+}:\mathrm{Y}\mathrm{V}{\mathrm{O}}_{4}$. We observe antiholes in the spectrum along with long lived spectral holes, which demonstrates optical pumping between the ground state Zeeman levels. The spectral holes are narrow (homogeneous linewidth of $63\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$) at $2.1\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ with a $300\phantom{\rule{0.3em}{0ex}}\mathrm{mT}$ applied magnetic field. We also perform preliminary spectral tailoring in this material by creating a $40\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$ wide transmission window in the inhomogeneous absorption. These results show the potential of the Zeeman levels in Nd doped materials to be used for spectral tailoring for quantum and classical information processing.

DOI: 10.1103/physrevb.77.125111

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Efficient spectral hole-burning and atomic frequency comb storage in Nd3+:YLiF4

Zong‐Quan Zhou, Jian Wang, Chuan‐Feng Li +1 more

We present spectral hole-burning measurements of the (4)I9/2 → (4)F3/2 transition in Nd(3+):YLiF4. The isotope shifts of Nd(3+) can be directly resolved in the optical absorption spectrum. We report atomic frequency comb storage with an echo efficiency of up to 35% and a memory bandwidth of 60 MHz in this material. The interesting properties show the potential of this material for use in both quantum and classical information processing.

arXiv:1309.6703Scientific ReportsSep 25, 20138 citations

Spectral hole burning by population storage in Zeeman sublevels of LaFsub3: Nd3+

R. M. Macfarlane, J. C. Vial

Physical review. B, Condensed matterSep 1, 198733 citations

Hole-burning techniques for isolation and study of individual hyperfine transitions in inhomogeneously broadened solids demonstrated in Pr3+:Y2SiO5

Mattias Nilsson, Lars Rippe, Stefan Kröll +2 more

arXiv:cond-mat/0408515Physical Review BDec 30, 2004201 citations

Spectral hole burning of Eu2+ in Ca F2

D.M. Boye, R. M. Macfarlane, Yazhou Sun +1 more

Physical review. B, Condensed matterSep 1, 199623 citations

Optical spectroscopy and decoherence studies of Yb3+ :YAG at 968 nm

Thomas Böttger, Charles W. Thiel, R. L. Cone +2 more

Physical review. B./Physical review. BJul 26, 201628 citations

Photon echo, spectral hole burning, and optically detected magnetic resonance in Yb 3 + 171 : LiNbO 3 bulk crystal and waveguides

F. Chiossi, Eloïse Lafitte-Houssat, Kangwei Xia +11 more

Physical review. B./Physical review. BMay 31, 20227 citations

Physical Review B

Spectral hole-burning spectroscopy in Nd 3 + : Y V O 4

Published Mar 10, 2008• 41 citations

Publisher

Abstract

We present spectral hole-burning measurements on the

879\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

^{4}I_{9∕2}\ensuremath{\rightarrow}^{4}F_{3∕2}

transition in

{\mathrm{Nd}}^{3+}:\mathrm{Y}\mathrm{V}{\mathrm{O}}_{4}

. We observe antiholes in the spectrum along with long lived spectral holes, which demonstrates optical pumping between the ground state Zeeman levels. The spectral holes are narrow (homogeneous linewidth of

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

) at

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

with a

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

applied magnetic field. We also perform preliminary spectral tailoring in this material by creating a

40\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}

wide transmission window in the inhomogeneous absorption. These results show the potential of the Zeeman levels in Nd doped materials to be used for spectral tailoring for quantum and classical information processing.

DOI: 10.1103/physrevb.77.125111

Related papers

Efficient spectral hole-burning and atomic frequency comb storage in Nd3+:YLiF4

Zong‐Quan Zhou, Jian Wang, Chuan‐Feng Li +1 more

arXiv:1309.6703Scientific ReportsSep 25, 20138 citations

Spectral hole burning by population storage in Zeeman sublevels of LaFsub3: Nd3+

R. M. Macfarlane, J. C. Vial

We demonstrate a new mechanism for optical spectral hole burning in which population is stored in electronic Zeeman sublevels. This is shown by optical pumping the ground-state Kramers doublet of the $^{4}\mathrm{I}_{9/2}$ ${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$ ${\mathrm{H}}_{11/2}$ (6248.9 A\r{}) and $^{4}\mathrm{I}_{9/2}$ ${\mathrm{\ensuremath{\leftrightarrows}}}^{4}$ ${\mathrm{G}}_{5/2}$ (5777.1 A\r{}) transitions of ${\mathrm{LaF}}_{3}$ : ${\mathrm{Nd}}^{3+}$ with a narrow-band cw dye laser. Experiments were carried out at 1.6 K in external fields of \ensuremath{\sim}100 G. The Zeeman shift of the resulting antiholes and holes makes an assignment of these structures possible. Hole recovery times of hundreds of milliseconds are shorter than expected at these low temperatures and fields and provide evidence for optical spectral diffusion caused by mutual spin flips in the ground state.We demonstrate a new mechanism for optical spectral hole burning in which population is stored in electronic Zeeman sublevels. This is shown by optical pumping the ground-state Kramers doublet of the $^{4}\mathrm{I}_{9/2}$${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$${\mathrm{H}}_{11/2}$ (6248.9 A\r{}) and $^{4}\mathrm{I}_{9/2}$${\mathrm{\ensuremath{\leftrightarrows}}}^{4}$${\mathrm{G}}_{5/2}$ (5777.1 A\r{}) transitions of ${\mathrm{LaF}}_{3}$:${\mathrm{Nd}}^{3+}$ with a narrow-band cw dye laser. Experiments were carried out at 1.6 K in external fields of \ensuremath{\sim}100 G. The Zeeman shift of the resulting antiholes and holes makes an assignment of these structures possible. Hole recovery times of hundreds of milliseconds are shorter than expected at these low temperatures and fields and provide evidence for optical spectral diffusion caused by mutual spin flips in the ground state.

Physical review. B, Condensed matterSep 1, 198733 citations

Hole-burning techniques for isolation and study of individual hyperfine transitions in inhomogeneously broadened solids demonstrated in Pr3+:Y2SiO5

Mattias Nilsson, Lars Rippe, Stefan Kröll +2 more

Due to their narrow homogeneous linewidths, rare-earth ions in inorganic crystals at low temperatures have recently been given considerable attention as test materials for experiments in coherent quantum optics. Because these narrow linewidth transitions have been buried in a wide inhomogeneous line, the scope of experiments that could be carried out in these materials has been limited. However, here we present spectroscopic techniques, based on spectral hole burning and optical pumping, which allow hyperfine transitions that are initially buried within an inhomogeneously broadened absorption line to be studied with no background absorption from other transitions. A sequence of hole-burning pulses is used to isolate selected transitions between hyperfine levels, which makes it possible to directly study properties of the transitions, e.g., transition strengths, and gives access to information that is difficult to obtain in standard hole-burning spectroscopy, such as the ordering of hyperfine levels. The techniques introduced are applicable to absorbers in a solid with long-lived sublevels in the ground state and where the homogeneous linewidth and sublevel separations are smaller than the inhomogeneous broadening of the optical transition. In particular, this includes rare-earth ions doped into inorganic crystals and in the present work the techniques are demonstrated in spectroscopy of ${\mathrm{Pr}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ . Information on the hyperfine structure and relative transition strengths of the $^{3}H_{4}\text{\ensuremath{-}}^{1}D_{2}$ hyperfine transitions in ${\mathrm{Pr}}^{3+}:{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ has been obtained from frequency-resolved absorption measurements, in combination with coherent and incoherent driving of the transitions.Due to their narrow homogeneous linewidths, rare-earth ions in inorganic crystals at low temperatures have recently been given considerable attention as test materials for experiments in coherent quantum optics. Because these narrow linewidth transitions have been buried in a wide inhomogeneous line, the scope of experiments that could be carried out in these materials has been limited. However, here we present spectroscopic techniques, based on spectral hole burning and optical pumping, which allow hyperfine transitions that are initially buried within an inhomogeneously broadened absorption line to be studied with no background absorption from other transitions. A sequence of hole-burning pulses is used to isolate selected transitions between hyperfine levels, which makes it possible to directly study properties of the transitions, e.g., transition strengths, and gives access to information that is difficult to obtain in standard hole-burning spectroscopy, such as the ordering of hyperfine levels. The techniques introduced are applicable to absorbers in a solid with long-lived sublevels in the ground state and where the homogeneous linewidth and sublevel separations are smaller than the inhomogeneous broadening of the optical transition. In particular, this includes rare-earth ions doped into inorganic crystals and in the present work the techniques are demonstrated in spectroscopy of ${\mathrm{Pr}}^{3+}$ in ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$. Information on the hyperfine structure and relative transition strengths of the $^{3}H_{4}\text{\ensuremath{-}}^{1}D_{2}$ hyperfine transitions in ${\mathrm{Pr}}^{3+}:{\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ has been obtained from frequency-resolved absorption measurements, in combination with coherent and incoherent driving of the transitions.

arXiv:cond-mat/0408515Physical Review BDec 30, 2004201 citations

Spectral hole burning of Eu2+ in Ca F2

D.M. Boye, R. M. Macfarlane, Yazhou Sun +1 more

Spectral hole burning on the $4{f}^{7}(^{8}S_{\frac{7}{2}})\ensuremath{\rightarrow}4{f}^{6}5d$ transition of ${\mathrm{Eu}}^{2+}$ is observed to occur by two mechanisms in Ca ${\mathrm{F}}_{2}$ : ${\mathrm{Eu}}^{2+}$ . At zero magnetic field, persistent spectral hole burning occurs by two-step photoionization where the hole burning survives cycling to room temperature. The observed hole spectrum is compared with a calculation which considers the small ${\mathrm{Eu}}^{2+}$ ground-state splitting and both the ground- and excited-state hyperfine interactions. In a magnetic field above 1 T, transient spectral hole burning occurs by population redistribution among the ground-state hyperfine levels. Long-lived (minutes) holes are observed for a half integral spin system. The resulting hole spectrum consists of holes, antiholes, and a nuclear spin-flip sideband and can be explained from the hyperfine interactions in the ground and excited states. The dominant hole decay occurs by phonon-induced transitions among hyperfine levels of the ${M}_{S}=\ensuremath{-}\frac{7}{2}$ and ${M}_{S}=\ensuremath{-}\frac{5}{2}$ electron-spin sublevels. Central hole linewidths of 200 MHz are observed at zero magnetic field. Hole linewidths at high magnetic fields are as narrow as 40 MHz but these are inhomogenously broadened by superhyperfine interactions with the $F$ nuclear spins. Estimates of hole-burning quantum efficiency are also obtained.Spectral hole burning on the $4{f}^{7}(^{8}S_{\frac{7}{2}})\ensuremath{\rightarrow}4{f}^{6}5d$ transition of ${\mathrm{Eu}}^{2+}$ is observed to occur by two mechanisms in Ca${\mathrm{F}}_{2}$:${\mathrm{Eu}}^{2+}$. At zero magnetic field, persistent spectral hole burning occurs by two-step photoionization where the hole burning survives cycling to room temperature. The observed hole spectrum is compared with a calculation which considers the small ${\mathrm{Eu}}^{2+}$ ground-state splitting and both the ground- and excited-state hyperfine interactions. In a magnetic field above 1 T, transient spectral hole burning occurs by population redistribution among the ground-state hyperfine levels. Long-lived (minutes) holes are observed for a half integral spin system. The resulting hole spectrum consists of holes, antiholes, and a nuclear spin-flip sideband and can be explained from the hyperfine interactions in the ground and excited states. The dominant hole decay occurs by phonon-induced transitions among hyperfine levels of the ${M}_{S}=\ensuremath{-}\frac{7}{2}$ and ${M}_{S}=\ensuremath{-}\frac{5}{2}$ electron-spin sublevels. Central hole linewidths of 200 MHz are observed at zero magnetic field. Hole linewidths at high magnetic fields are as narrow as 40 MHz but these are inhomogenously broadened by superhyperfine interactions with the $F$ nuclear spins. Estimates of hole-burning quantum efficiency are also obtained.

Physical review. B, Condensed matterSep 1, 199623 citations

Optical spectroscopy and decoherence studies of Yb3+ :YAG at 968 nm

Thomas Böttger, Charles W. Thiel, R. L. Cone +2 more

The $^{2}F_{7/2}\ensuremath{\leftrightarrow}^{2}F_{5/2}$ optical transitions of $\mathrm{Y}{\mathrm{b}}^{3+}$ doped into ${\mathrm{Y}}_{3}\mathrm{A}{\mathrm{l}}_{5}{\mathrm{O}}_{12}$ (YAG) were studied for potential quantum information and photonic signal processing applications. Absorption and fluorescence spectroscopy located the energy levels of the ground $^{2}F_{7/2}$ and excited $^{2}F_{5/2}$ manifolds, allowing inconsistencies between previous assignments of crystal field splittings in the literature to be resolved. These measurements reveal an unusually large splitting between the first and second levels in both the ground and excited multiplets, potentially providing for reduced sensitivity to thermally induced decoherence and spin-lattice relaxation. Spectral hole burning through two-level saturation was observed, determining the excited state lifetime to be 860 \ensuremath{\mu}s and resolving ambiguities in previous fluorescence measurements that were caused by the large radiation trapping effects in this material. Optical decoherence measurements using two-pulse photon echoes gave a homogeneous linewidth of 18 kHz for an applied magnetic field of 1 T, narrowing to 5 kHz at 2.5 T. The observed decoherence was described by spectral diffusion attributed to $\mathrm{Y}{\mathrm{b}}^{3+}\mathrm{\ensuremath{-}}\mathrm{Y}{\mathrm{b}}^{3+}$ magnetic dipole interactions. Laser absorption determined an inhomogeneous linewidth of 3.6 GHz for this transition in this 0.05%-doped crystal, which is narrower than for any other rare-earth-ion transition previously studied in the YAG host. The temperature dependence of the transition energy and linewidth of the lowest $^{2}F_{7/2}$ to lowest $^{2}F_{5/2}$ transition centered at 968.571 nm measured from 4 K to 300 K was well described by phonon scattering at higher temperatures, with an additional anomalous linear temperature-dependent broadening at temperatures below 80 K. Two magnetically inequivalent subgroups of $\mathrm{Y}{\mathrm{b}}^{3+}$ ions were identified when a magnetic field was applied along the $\ensuremath{\langle}111\ensuremath{\rangle}$ axis, as expected for the ${D}_{2}$ sites in the cubic symmetry crystal, with ground and excited state effective $g$ -values of ${g}_{\mathrm{g}}=3.40$ (3.34) and ${g}_{\mathrm{e}}=1.04$ (2.01), respectively. Together with the convenient diode laser wavelength of this transition, our study suggests that $\mathrm{Y}{\mathrm{b}}^{3+}$ :YAG is a promising material system for spectral hole burning and quantum information applications.The $^{2}F_{7/2}\ensuremath{\leftrightarrow}^{2}F_{5/2}$ optical transitions of $\mathrm{Y}{\mathrm{b}}^{3+}$ doped into ${\mathrm{Y}}_{3}\mathrm{A}{\mathrm{l}}_{5}{\mathrm{O}}_{12}$ (YAG) were studied for potential quantum information and photonic signal processing applications. Absorption and fluorescence spectroscopy located the energy levels of the ground $^{2}F_{7/2}$ and excited $^{2}F_{5/2}$ manifolds, allowing inconsistencies between previous assignments of crystal field splittings in the literature to be resolved. These measurements reveal an unusually large splitting between the first and second levels in both the ground and excited multiplets, potentially providing for reduced sensitivity to thermally induced decoherence and spin-lattice relaxation. Spectral hole burning through two-level saturation was observed, determining the excited state lifetime to be 860 \ensuremath{\mu}s and resolving ambiguities in previous fluorescence measurements that were caused by the large radiation trapping effects in this material. Optical decoherence measurements using two-pulse photon echoes gave a homogeneous linewidth of 18 kHz for an applied magnetic field of 1 T, narrowing to 5 kHz at 2.5 T. The observed decoherence was described by spectral diffusion attributed to $\mathrm{Y}{\mathrm{b}}^{3+}\mathrm{\ensuremath{-}}\mathrm{Y}{\mathrm{b}}^{3+}$ magnetic dipole interactions. Laser absorption determined an inhomogeneous linewidth of 3.6 GHz for this transition in this 0.05%-doped crystal, which is narrower than for any other rare-earth-ion transition previously studied in the YAG host. The temperature dependence of the transition energy and linewidth of the lowest $^{2}F_{7/2}$ to lowest $^{2}F_{5/2}$ transition centered at 968.571 nm measured from 4 K to 300 K was well described by phonon scattering at higher temperatures, with an additional anomalous linear temperature-dependent broadening at temperatures below 80 K. Two magnetically inequivalent subgroups of $\mathrm{Y}{\mathrm{b}}^{3+}$ ions were identified when a magnetic field was applied along the $\ensuremath{\langle}111\ensuremath{\rangle}$ axis, as expected for the ${D}_{2}$ sites in the cubic symmetry crystal, with ground and excited state effective $g$-values of ${g}_{\mathrm{g}}=3.40$ (3.34) and ${g}_{\mathrm{e}}=1.04$ (2.01), respectively. Together with the convenient diode laser wavelength of this transition, our study suggests that $\mathrm{Y}{\mathrm{b}}^{3+}$:YAG is a promising material system for spectral hole burning and quantum information applications.

Physical review. B./Physical review. BJul 26, 201628 citations

Photon echo, spectral hole burning, and optically detected magnetic resonance in Yb 3 + 171 : LiNbO 3 bulk crystal and waveguides

F. Chiossi, Eloïse Lafitte-Houssat, Kangwei Xia +11 more

Recent progress in the realization of high-quality optical resonators and waveguides along with the possibility to incorporate rare-earth ions, make lithium niobate a promising material to build integrated platforms for quantum information processing. $^{171}\mathrm{Yb}^{3+}$ is a particularly attractive system because it can show long coherence lifetimes at zero magnetic field thanks to transitions insensitive to magnetic field fluctuations. In this paper, we investigate the optical and spin properties of $^{171}\mathrm{Yb}^{3+}$ ions in ${\mathrm{LiNbO}}_{3}$ bulk crystals as well as implanted waveguides. Using hole-burning spectroscopy and optically detected magnetic resonance, we studied ground and excited state hyperfine structures and probed optical and spin spectral holes. Importantly, the hole linewidths suggest that part of the ions in the waveguides are in a similar environment as in the bulk sample. We furthermore characterized spin population relaxation and coherence lifetimes of $^{171}\mathrm{Yb}^{3+}$ ions in the bulk crystal at temperatures between 50 mK and 9 K. At low temperatures, ${T}_{2}$ up to 9.5 $\ensuremath{\mu}\mathrm{s}$ (34 kHz homogeneous linewidth) and spin relaxation rates as long as $\ensuremath{\approx}100$ ms were measured. Our results show that $^{171}\mathrm{Yb}^{3+}$ : $\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_{3}$ is a system that exhibits narrow optical homogeneous linewidths over a 50 GHz bandwidth together with an electron spin degree of freedom. This is of interest for a variety of applications in integrated quantum photonics such as quantum memories or quantum processors.Recent progress in the realization of high-quality optical resonators and waveguides along with the possibility to incorporate rare-earth ions, make lithium niobate a promising material to build integrated platforms for quantum information processing. $^{171}\mathrm{Yb}^{3+}$ is a particularly attractive system because it can show long coherence lifetimes at zero magnetic field thanks to transitions insensitive to magnetic field fluctuations. In this paper, we investigate the optical and spin properties of $^{171}\mathrm{Yb}^{3+}$ ions in ${\mathrm{LiNbO}}_{3}$ bulk crystals as well as implanted waveguides. Using hole-burning spectroscopy and optically detected magnetic resonance, we studied ground and excited state hyperfine structures and probed optical and spin spectral holes. Importantly, the hole linewidths suggest that part of the ions in the waveguides are in a similar environment as in the bulk sample. We furthermore characterized spin population relaxation and coherence lifetimes of $^{171}\mathrm{Yb}^{3+}$ ions in the bulk crystal at temperatures between 50 mK and 9 K. At low temperatures, ${T}_{2}$ up to 9.5 $\ensuremath{\mu}\mathrm{s}$ (34 kHz homogeneous linewidth) and spin relaxation rates as long as $\ensuremath{\approx}100$ ms were measured. Our results show that $^{171}\mathrm{Yb}^{3+}$:$\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_{3}$ is a system that exhibits narrow optical homogeneous linewidths over a 50 GHz bandwidth together with an electron spin degree of freedom. This is of interest for a variety of applications in integrated quantum photonics such as quantum memories or quantum processors.

Physical review. B./Physical review. BMay 31, 20227 citations

We present spectral hole-burning measurements on the

879\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

^{4}I_{9∕2}\ensuremath{\rightarrow}^{4}F_{3∕2}

transition in

{\mathrm{Nd}}^{3+}:\mathrm{Y}\mathrm{V}{\mathrm{O}}_{4}

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

) at

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

with a

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

applied magnetic field. We also perform preliminary spectral tailoring in this material by creating a

40\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}

We demonstrate a new mechanism for optical spectral hole burning in which population is stored in electronic Zeeman sublevels. This is shown by optical pumping the ground-state Kramers doublet of the

^{4}\mathrm{I}_{9/2}

${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$

{\mathrm{H}}_{11/2}

(6248.9 A\r{}) and

^{4}\mathrm{I}_{9/2}

${\mathrm{\ensuremath{\leftrightarrows}}}^{4}$

{\mathrm{G}}_{5/2}

(5777.1 A\r{}) transitions of

{\mathrm{LaF}}_{3}

{\mathrm{Nd}}^{3+}

with a narrow-band cw dye laser. Experiments were carried out at 1.6 K in external fields of \ensuremath{\sim}100 G. The Zeeman shift of the resulting antiholes and holes makes an assignment of these structures possible. Hole recovery times of hundreds of milliseconds are shorter than expected at these low temperatures and fields and provide evidence for optical spectral diffusion caused by mutual spin flips in the ground state.

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

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

. Information on the hyperfine structure and relative transition strengths of the $^{3}H_{4}\text{\ensuremath{-}}^{1}D_{2}$ hyperfine transitions in

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

has been obtained from frequency-resolved absorption measurements, in combination with coherent and incoherent driving of the transitions.

Spectral hole burning on the $4{f}^{7}(^{8}S_{\frac{7}{2}})\ensuremath{\rightarrow}4{f}^{6}5d$ transition of

{\mathrm{Eu}}^{2+}

is observed to occur by two mechanisms in Ca

{\mathrm{F}}_{2}

{\mathrm{Eu}}^{2+}

. At zero magnetic field, persistent spectral hole burning occurs by two-step photoionization where the hole burning survives cycling to room temperature. The observed hole spectrum is compared with a calculation which considers the small

{\mathrm{Eu}}^{2+}

ground-state splitting and both the ground- and excited-state hyperfine interactions. In a magnetic field above 1 T, transient spectral hole burning occurs by population redistribution among the ground-state hyperfine levels. Long-lived (minutes) holes are observed for a half integral spin system. The resulting hole spectrum consists of holes, antiholes, and a nuclear spin-flip sideband and can be explained from the hyperfine interactions in the ground and excited states. The dominant hole decay occurs by phonon-induced transitions among hyperfine levels of the ${M}_{S}=\ensuremath{-}\frac{7}{2}$ and ${M}_{S}=\ensuremath{-}\frac{5}{2}$ electron-spin sublevels. Central hole linewidths of 200 MHz are observed at zero magnetic field. Hole linewidths at high magnetic fields are as narrow as 40 MHz but these are inhomogenously broadened by superhyperfine interactions with the

F

nuclear spins. Estimates of hole-burning quantum efficiency are also obtained.

The $^{2}F_{7/2}\ensuremath{\leftrightarrow}^{2}F_{5/2}$ optical transitions of

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

doped into

{\mathrm{Y}}_{3}\mathrm{A}{\mathrm{l}}_{5}{\mathrm{O}}_{12}

(YAG) were studied for potential quantum information and photonic signal processing applications. Absorption and fluorescence spectroscopy located the energy levels of the ground

^{2}F_{7/2}

and excited

^{2}F_{5/2}

manifolds, allowing inconsistencies between previous assignments of crystal field splittings in the literature to be resolved. These measurements reveal an unusually large splitting between the first and second levels in both the ground and excited multiplets, potentially providing for reduced sensitivity to thermally induced decoherence and spin-lattice relaxation. Spectral hole burning through two-level saturation was observed, determining the excited state lifetime to be 860 \ensuremath{\mu}s and resolving ambiguities in previous fluorescence measurements that were caused by the large radiation trapping effects in this material. Optical decoherence measurements using two-pulse photon echoes gave a homogeneous linewidth of 18 kHz for an applied magnetic field of 1 T, narrowing to 5 kHz at 2.5 T. The observed decoherence was described by spectral diffusion attributed to $\mathrm{Y}{\mathrm{b}}^{3+}\mathrm{\ensuremath{-}}\mathrm{Y}{\mathrm{b}}^{3+}$ magnetic dipole interactions. Laser absorption determined an inhomogeneous linewidth of 3.6 GHz for this transition in this 0.05%-doped crystal, which is narrower than for any other rare-earth-ion transition previously studied in the YAG host. The temperature dependence of the transition energy and linewidth of the lowest

^{2}F_{7/2}

to lowest

^{2}F_{5/2}

transition centered at 968.571 nm measured from 4 K to 300 K was well described by phonon scattering at higher temperatures, with an additional anomalous linear temperature-dependent broadening at temperatures below 80 K. Two magnetically inequivalent subgroups of

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

ions were identified when a magnetic field was applied along the $\ensuremath{\langle}111\ensuremath{\rangle}$ axis, as expected for the

{D}_{2}

sites in the cubic symmetry crystal, with ground and excited state effective

g

-values of

{g}_{\mathrm{g}}=3.40

(3.34) and

{g}_{\mathrm{e}}=1.04

(2.01), respectively. Together with the convenient diode laser wavelength of this transition, our study suggests that

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

:YAG is a promising material system for spectral hole burning and quantum information applications.

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

is a particularly attractive system because it can show long coherence lifetimes at zero magnetic field thanks to transitions insensitive to magnetic field fluctuations. In this paper, we investigate the optical and spin properties of

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

ions in

{\mathrm{LiNbO}}_{3}

bulk crystals as well as implanted waveguides. Using hole-burning spectroscopy and optically detected magnetic resonance, we studied ground and excited state hyperfine structures and probed optical and spin spectral holes. Importantly, the hole linewidths suggest that part of the ions in the waveguides are in a similar environment as in the bulk sample. We furthermore characterized spin population relaxation and coherence lifetimes of

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

ions in the bulk crystal at temperatures between 50 mK and 9 K. At low temperatures,

{T}_{2}

up to 9.5 $\ensuremath{\mu}\mathrm{s}$ (34 kHz homogeneous linewidth) and spin relaxation rates as long as $\ensuremath{\approx}100$ ms were measured. Our results show that

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

\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_{3}

is a system that exhibits narrow optical homogeneous linewidths over a 50 GHz bandwidth together with an electron spin degree of freedom. This is of interest for a variety of applications in integrated quantum photonics such as quantum memories or quantum processors.