Physical Review B

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

O. Guillot-Noël, Philippe Goldner, Y. Le Du, Pascal Loiseau, Brian Julsgaard, Lars Rippe, Stefan Kröll

Published May 15, 2007• 19 citations

Abstract

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.

DOI: 10.1103/physrevb.75.205110

Related papers

Hyperfine structure and homogeneous broadening in Pr3+:KY(WO4)2

H. L. Xu, M. Nilsson, S. Ohser +4 more

Physical Review BDec 30, 20048 citations

Hyperfine structure and hyperfine coherent properties of praseodymium in single-crystalline La2(WO4)3 by hole-burning and photon-echo techniques

O. Guillot-Noël, Philippe Goldner, Florian Beaudoux +6 more

Physical Review BApr 27, 200930 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

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

Homogeneous broadening and hyperfine structure of optical transitions in Pr 3 + : Y 2 SiO 5

Randy W. Equall, R. L. Cone, R. M. Macfarlane

Physical review. B, Condensed matterAug 1, 1995213 citations

Photon echo studies of rare-earth-activated materials for optical memory and signal processing devices

Randy W. Equall

Jan 1, 19951 citation

Physical Review B

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

O. Guillot-Noël, Philippe Goldner, Y. Le Du, Pascal Loiseau, Brian Julsgaard, Lars Rippe, Stefan Kröll

Published May 15, 2007• 19 citations

Publisher

Abstract

^{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}

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.

DOI: 10.1103/physrevb.75.205110

Related papers

Hyperfine structure and homogeneous broadening in Pr3+:KY(WO4)2

H. L. Xu, M. Nilsson, S. Ohser +4 more

As part of a search for suitable materials for coherent quantum operations, relaxation times and hyperfine structure of the $^{1}D_{2}(1)\text{\ensuremath{-}}^{3}H_{4}(1)$ transition in ${\mathrm{Pr}}^{3+}:\mathrm{KY}{({\mathrm{WO}}_{4})}_{2}$ (0.29 at. %) at 4 K have been obtained using photon-echo and spectral hole burning techniques. The homogeneous linewidth and the effect of excitation-induced dephasing were measured using two-pulse photon-echo techniques. Linewidths of $23.4\ifmmode\pm\else\textpm\fi{}1.0$ and $17.6\ifmmode\pm\else\textpm\fi{}0.9\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ were obtained in the absence and presence of an external magnetic field of about 9 mT. The radiative lifetime $({T}_{1})$ of the $^{1}D_{2}$ state was measured to be $43\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ using time-resolved laser-induced fluorescence and three-pulse photon-echo measurements. The transmission hole spectra were measured and directly yielded the quadrupole level splitting in the $^{1}D_{2}$ ($3.77\ifmmode\pm\else\textpm\fi{}0.03$ and $4.58\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) and $^{3}H_{4}$ ($17.1\ifmmode\pm\else\textpm\fi{}0.1$ and $33.2\ifmmode\pm\else\textpm\fi{}0.3\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) states. The spectral hole lifetime due to population redistribution between the ground-state nuclear levels was also determined to be $70\ifmmode\pm\else\textpm\fi{}10\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$. A strong dipole-dipole interaction observed in this crystal opens for potential applications in quantum computing schemes for performing quantum logic operations, but the short dephasing time makes it less useful in data storage applications.As part of a search for suitable materials for coherent quantum operations, relaxation times and hyperfine structure of the $^{1}D_{2}(1)\text{\ensuremath{-}}^{3}H_{4}(1)$ transition in ${\mathrm{Pr}}^{3+}:\mathrm{KY}{({\mathrm{WO}}_{4})}_{2}$ (0.29 at. %) at 4 K have been obtained using photon-echo and spectral hole burning techniques. The homogeneous linewidth and the effect of excitation-induced dephasing were measured using two-pulse photon-echo techniques. Linewidths of $23.4\ifmmode\pm\else\textpm\fi{}1.0$ and $17.6\ifmmode\pm\else\textpm\fi{}0.9\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ were obtained in the absence and presence of an external magnetic field of about 9 mT. The radiative lifetime $({T}_{1})$ of the $^{1}D_{2}$ state was measured to be $43\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ using time-resolved laser-induced fluorescence and three-pulse photon-echo measurements. The transmission hole spectra were measured and directly yielded the quadrupole level splitting in the $^{1}D_{2}$ ($3.77\ifmmode\pm\else\textpm\fi{}0.03$ and $4.58\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) and $^{3}H_{4}$ ($17.1\ifmmode\pm\else\textpm\fi{}0.1$ and $33.2\ifmmode\pm\else\textpm\fi{}0.3\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) states. The spectral hole lifetime due to population redistribution between the ground-state nuclear levels was also determined to be $70\ifmmode\pm\else\textpm\fi{}10\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$. A strong dipole-dipole interaction observed in this crystal opens for potential applications in quantum computing schemes for performing quantum logic operations, but the short dephasing time makes it less useful in data storage applications.

Physical Review BDec 30, 20048 citations

Hyperfine structure and hyperfine coherent properties of praseodymium in single-crystalline La2(WO4)3 by hole-burning and photon-echo techniques

O. Guillot-Noël, Philippe Goldner, Florian Beaudoux +6 more

We studied the hyperfine structure and hyperfine coherent properties of the ${^{3}\text{H}}_{4}(0)\ensuremath{\rightarrow}{^{1}\text{D}}_{2}(0)$ transition of ${\text{Pr}}^{3+}$ ions in a tungstate single crystal ${\text{La}}_{2}{({\text{WO}}_{4})}_{3}$ by hole-burning and photon-echo techniques. This work is motivated by the search of an efficient three level $\ensuremath{\Lambda}$ system in this new compound with which we could build up a quantum memory. By nonconventional hole-burning experiments, the ordering of the hyperfine splittings in the ${^{3}\text{H}}_{4}(0)$ ground state and in the ${^{1}\text{D}}_{2}(0)$ excited state is obtained. The hyperfine splittings are thus ordered: 24.6 and 14.9 MHz for the ${^{3}\text{H}}_{4}(0)$ level and 5.0 and 7.3 MHz for the ${^{1}\text{D}}_{2}(0)$ level. The relative and absolute transition strengths of individual hyperfine transitions are determined by comparing absorption strengths and by measuring the Rabi flopping frequency as the transition is coherently driven. Free induction and Raman echo decays give inhomogeneous and homogeneous hyperfine linewidths of $57\ifmmode\pm\else\textpm\fi{}2$ and $1.25\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{kHz}$, respectively.We studied the hyperfine structure and hyperfine coherent properties of the ${^{3}\text{H}}_{4}(0)\ensuremath{\rightarrow}{^{1}\text{D}}_{2}(0)$ transition of ${\text{Pr}}^{3+}$ ions in a tungstate single crystal ${\text{La}}_{2}{({\text{WO}}_{4})}_{3}$ by hole-burning and photon-echo techniques. This work is motivated by the search of an efficient three level $\ensuremath{\Lambda}$ system in this new compound with which we could build up a quantum memory. By nonconventional hole-burning experiments, the ordering of the hyperfine splittings in the ${^{3}\text{H}}_{4}(0)$ ground state and in the ${^{1}\text{D}}_{2}(0)$ excited state is obtained. The hyperfine splittings are thus ordered: 24.6 and 14.9 MHz for the ${^{3}\text{H}}_{4}(0)$ level and 5.0 and 7.3 MHz for the ${^{1}\text{D}}_{2}(0)$ level. The relative and absolute transition strengths of individual hyperfine transitions are determined by comparing absorption strengths and by measuring the Rabi flopping frequency as the transition is coherently driven. Free induction and Raman echo decays give inhomogeneous and homogeneous hyperfine linewidths of $57\ifmmode\pm\else\textpm\fi{}2$ and $1.25\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{kHz}$, respectively.

Physical Review BApr 27, 200930 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

Homogeneous broadening and hyperfine structure of optical transitions in Pr 3 + : Y 2 SiO 5

Randy W. Equall, R. L. Cone, R. M. Macfarlane

Contributions to the homogeneous linewidth of the $^{3}$ ${\mathit{H}}_{4}$ (1)${\ensuremath{\rightarrow}}^{1}$ ${\mathit{D}}_{2}$ (1) transition for the two crystallographic sites of ${\mathrm{Pr}}^{3+}$ in ${\mathrm{Y}}_{2}$ ${\mathrm{SiO}}_{5}$ have been investigated using photon echoes. The effects of excitation-intensity-dependent dephasing or instantaneous diffusion were systematically studied to allow accurate determination of the optical resonance widths. Homogeneous linewidths of 2.8 kHz (site 1) and 1 kHz (site 2) were measured with no applied magnetic field and with sufficiently low laser intensity to minimize the effects of instantaneous diffusion. Using the same excitation intensity, widths of 2.1 kHz (site 1) and 0.85 kHz (site 2) were obtained with an applied magnetic field of 77 G, demonstrating a significant contribution of $^{89}\mathrm{Y}$ nuclear-spin fluctuations to the zero-field homogeneous linewidth. Extrapolation to zero excitation intensity yielded optical resonance widths that were only slightly narrower than the measured values. Optically detected nuclear magnetic resonance measurements determined the hyperfine structure of the $^{3}$ ${\mathit{H}}_{4}$ ground state for each site; the hyperfine levels of the lowest component of the $^{1}$ ${\mathit{D}}_{2}$ manifold for each site were determined using photon echo nuclear double resonance. The relatively large oscillator strength of 3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}7}$ for a rare-earth ion, in conjunction with long dephasing times makes this material a useful candidate for demonstration of time-domain signal processing and optical data storage.Contributions to the homogeneous linewidth of the $^{3}$${\mathit{H}}_{4}$(1)${\ensuremath{\rightarrow}}^{1}$${\mathit{D}}_{2}$(1) transition for the two crystallographic sites of ${\mathrm{Pr}}^{3+}$ in ${\mathrm{Y}}_{2}$${\mathrm{SiO}}_{5}$ have been investigated using photon echoes. The effects of excitation-intensity-dependent dephasing or instantaneous diffusion were systematically studied to allow accurate determination of the optical resonance widths. Homogeneous linewidths of 2.8 kHz (site 1) and 1 kHz (site 2) were measured with no applied magnetic field and with sufficiently low laser intensity to minimize the effects of instantaneous diffusion. Using the same excitation intensity, widths of 2.1 kHz (site 1) and 0.85 kHz (site 2) were obtained with an applied magnetic field of 77 G, demonstrating a significant contribution of $^{89}\mathrm{Y}$ nuclear-spin fluctuations to the zero-field homogeneous linewidth. Extrapolation to zero excitation intensity yielded optical resonance widths that were only slightly narrower than the measured values. Optically detected nuclear magnetic resonance measurements determined the hyperfine structure of the $^{3}$${\mathit{H}}_{4}$ ground state for each site; the hyperfine levels of the lowest component of the $^{1}$${\mathit{D}}_{2}$ manifold for each site were determined using photon echo nuclear double resonance. The relatively large oscillator strength of 3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}7}$ for a rare-earth ion, in conjunction with long dephasing times makes this material a useful candidate for demonstration of time-domain signal processing and optical data storage.

Physical review. B, Condensed matterAug 1, 1995213 citations

Photon echo studies of rare-earth-activated materials for optical memory and signal processing devices

Randy W. Equall

The optical spectroscopy and dynamics of three materials; Eu^3+:Y2SiO5, Pr^3+:Y2SiO5, and Tm^3+:Y2SiO5 that are of interest for application in persistent spectral holeburning optical memory and signal processing devices were investigated using linear and nonlinear spectroscopic techniques.Two-pulse photon echoes have been used to measure the homogeneous linewidths.The effects of instantaneous spectral diffusion were systematically studied to allow accurate determination of the optical resonance widths, and external magnetic fields were applied to characterize the effects of fluctuating nuclear spins of the host lattice on dephasing of the dopant ion.The 7F0 → 5D0 transition of 0.1% Eu^3+ in the two crystallographic sites of Y2SiO5 was studied using photon echoes.Using this material, we succeeded in measuring the narrowest optical resonance in a solid by shielding the crystal from stray electromagnetic fields and using sufficiently low laser power to minimize contributions from instantaneous diffusion.The homogeneous linewidths measured in a magnetic field of 100 G are 122 Hz (site 1) and 167 Hz (site 2).These widths are dominated by population decay, but up to 20 Hz is attributed to 89Y spin fluctuations which have been reduced by the applied magnetic field.Similar studies were performed to determine the contributions to the homogeneous linewidth of the 3H4(1) → 1D2(1) transition for both sites of 0.02% Pr^3+ in Y2SiO5.Linewidths of 2.1 kHz (site 1) and 0.85 kHz (site 2) were obtained with an applied magnetic field of 77 G.A significant contribution of 89Y nuclear spin fluctuations to the zero-field homogeneous linewidth was found.Optically detected nuclear magnetic resonance measurements determined the hyperfine structure of the 3H4 ground state for each site, and photon echo nuclear double resonance was used to determine the hyperfine levels of the lowest component of the 1D2 manifold. 3) 2.1? Ec,2SThe optical spectroscopy and dynamics of three materials; Eu^3+:Y2SiO5, Pr^3+:Y2SiO5, and Tm^3+:Y2SiO5 that are of interest for application in persistent spectral holeburning optical memory and signal processing devices were investigated using linear and nonlinear spectroscopic techniques.Two-pulse photon echoes have been used to measure the homogeneous linewidths.The effects of instantaneous spectral diffusion were systematically studied to allow accurate determination of the optical resonance widths, and external magnetic fields were applied to characterize the effects of fluctuating nuclear spins of the host lattice on dephasing of the dopant ion.The 7F0 → 5D0 transition of 0.1% Eu^3+ in the two crystallographic sites of Y2SiO5 was studied using photon echoes.Using this material, we succeeded in measuring the narrowest optical resonance in a solid by shielding the crystal from stray electromagnetic fields and using sufficiently low laser power to minimize contributions from instantaneous diffusion.The homogeneous linewidths measured in a magnetic field of 100 G are 122 Hz (site 1) and 167 Hz (site 2).These widths are dominated by population decay, but up to 20 Hz is attributed to 89Y spin fluctuations which have been reduced by the applied magnetic field.Similar studies were performed to determine the contributions to the homogeneous linewidth of the 3H4(1) → 1D2(1) transition for both sites of 0.02% Pr^3+ in Y2SiO5.Linewidths of 2.1 kHz (site 1) and 0.85 kHz (site 2) were obtained with an applied magnetic field of 77 G.A significant contribution of 89Y nuclear spin fluctuations to the zero-field homogeneous linewidth was found.Optically detected nuclear magnetic resonance measurements determined the hyperfine structure of the 3H4 ground state for each site, and photon echo nuclear double resonance was used to determine the hyperfine levels of the lowest component of the 1D2 manifold. 3) 2.1? Ec,2S

Jan 1, 19951 citation

^{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}

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}

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.

As part of a search for suitable materials for coherent quantum operations, relaxation times and hyperfine structure of the $^{1}D_{2}(1)\text{\ensuremath{-}}^{3}H_{4}(1)$ transition in

{\mathrm{Pr}}^{3+}:\mathrm{KY}{({\mathrm{WO}}_{4})}_{2}

(0.29 at. %) at 4 K have been obtained using photon-echo and spectral hole burning techniques. The homogeneous linewidth and the effect of excitation-induced dephasing were measured using two-pulse photon-echo techniques. Linewidths of $23.4\ifmmode\pm\else\textpm\fi{}1.0$ and $17.6\ifmmode\pm\else\textpm\fi{}0.9\phantom{\rule{0.3em}{0ex}}\mathrm{kHz}$ were obtained in the absence and presence of an external magnetic field of about 9 mT. The radiative lifetime

({T}_{1})

of the

^{1}D_{2}

state was measured to be $43\ifmmode\pm\else\textpm\fi{}2\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ using time-resolved laser-induced fluorescence and three-pulse photon-echo measurements. The transmission hole spectra were measured and directly yielded the quadrupole level splitting in the

^{1}D_{2}

($3.77\ifmmode\pm\else\textpm\fi{}0.03$ and $4.58\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) and

^{3}H_{4}

($17.1\ifmmode\pm\else\textpm\fi{}0.1$ and $33.2\ifmmode\pm\else\textpm\fi{}0.3\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$) states. The spectral hole lifetime due to population redistribution between the ground-state nuclear levels was also determined to be $70\ifmmode\pm\else\textpm\fi{}10\phantom{\rule{0.3em}{0ex}}\mathrm{ms}$. A strong dipole-dipole interaction observed in this crystal opens for potential applications in quantum computing schemes for performing quantum logic operations, but the short dephasing time makes it less useful in data storage applications.

We studied the hyperfine structure and hyperfine coherent properties of the ${^{3}\text{H}}_{4}(0)\ensuremath{\rightarrow}{^{1}\text{D}}_{2}(0)$ transition of

{\text{Pr}}^{3+}

ions in a tungstate single crystal

{\text{La}}_{2}{({\text{WO}}_{4})}_{3}

by hole-burning and photon-echo techniques. This work is motivated by the search of an efficient three level $\ensuremath{\Lambda}$ system in this new compound with which we could build up a quantum memory. By nonconventional hole-burning experiments, the ordering of the hyperfine splittings in the

{^{3}\text{H}}_{4}(0)

ground state and in the

{^{1}\text{D}}_{2}(0)

excited state is obtained. The hyperfine splittings are thus ordered: 24.6 and 14.9 MHz for the

{^{3}\text{H}}_{4}(0)

level and 5.0 and 7.3 MHz for the

{^{1}\text{D}}_{2}(0)

level. The relative and absolute transition strengths of individual hyperfine transitions are determined by comparing absorption strengths and by measuring the Rabi flopping frequency as the transition is coherently driven. Free induction and Raman echo decays give inhomogeneous and homogeneous hyperfine linewidths of $57\ifmmode\pm\else\textpm\fi{}2$ and $1.25\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{kHz}$, respectively.

Contributions to the homogeneous linewidth of the

^{3}

{\mathit{H}}_{4}

(1)${\ensuremath{\rightarrow}}^{1}$

{\mathit{D}}_{2}

(1) transition for the two crystallographic sites of

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

{\mathrm{Y}}_{2}

{\mathrm{SiO}}_{5}

have been investigated using photon echoes. The effects of excitation-intensity-dependent dephasing or instantaneous diffusion were systematically studied to allow accurate determination of the optical resonance widths. Homogeneous linewidths of 2.8 kHz (site 1) and 1 kHz (site 2) were measured with no applied magnetic field and with sufficiently low laser intensity to minimize the effects of instantaneous diffusion. Using the same excitation intensity, widths of 2.1 kHz (site 1) and 0.85 kHz (site 2) were obtained with an applied magnetic field of 77 G, demonstrating a significant contribution of

^{89}\mathrm{Y}

nuclear-spin fluctuations to the zero-field homogeneous linewidth. Extrapolation to zero excitation intensity yielded optical resonance widths that were only slightly narrower than the measured values. Optically detected nuclear magnetic resonance measurements determined the hyperfine structure of the

^{3}

{\mathit{H}}_{4}

ground state for each site; the hyperfine levels of the lowest component of the

^{1}

{\mathit{D}}_{2}

manifold for each site were determined using photon echo nuclear double resonance. The relatively large oscillator strength of 3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}7}$ for a rare-earth ion, in conjunction with long dephasing times makes this material a useful candidate for demonstration of time-domain signal processing and optical data storage.