Physical Review Letters

Excitation-induced frequency shift probed by stimulated photon echoes

Masaharu Mitsunaga, T. Takagahara, Ryuzi Yano, Naoshi Uesugi

Published May 25, 1992• 48 citations

Abstract

A stimulated photon-echo study has verified the instantaneous shift (\ensuremath{\le}1 MHz) and subsequent restoration (\ensuremath{\sim}2 ms) of the transition frequency of an impurity ion in a solid when its neighboring ions are exposed to pulsed optical excitation. Experiments were conducted by monitoring the echo intensity for the $^{7}$${\mathit{F}}_{0\mathrm{\ensuremath{-}}}^{5}$${\mathit{D}}_{0}$ transition of Eu ions in one site of ${\mathrm{Y}}_{2}$${\mathrm{SiO}}_{5}$, while exciting the other site. A photon-echo theory taking account of the stochastic frequency recovery is developed to explain the observations.

DOI: 10.1103/physrevlett.68.3216

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Physical Review Letters

Excitation-induced frequency shift probed by stimulated photon echoes

Masaharu Mitsunaga, T. Takagahara, Ryuzi Yano, Naoshi Uesugi

Published May 25, 1992• 48 citations

Publisher

Abstract

^{7}$${\mathit{F}}_{0\mathrm{\ensuremath{-}}}^{5}$${\mathit{D}}_{0}

transition of Eu ions in one site of

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

, while exciting the other site. A photon-echo theory taking account of the stochastic frequency recovery is developed to explain the observations.

DOI: 10.1103/physrevlett.68.3216

Related papers

Excess dephasing in photon-echo experiments arising from excitation-induced electronic level shifts

Huang Jin, J.M. Zhang, A. Lezama +1 more

Working on the $^{7}\mathrm{F}_{0}$ ${\mathrm{\ensuremath{-}}}^{5}$ ${\mathrm{D}}_{0}$ transition of ${\mathrm{Eu}}^{3+}$ in ${\mathrm{Y}}_{2}$ ${\mathrm{O}}_{3}$ , we provide the first detailed characterization of excitation-induced shifts in optical transition frequencies and demonstrate their exaggeration of nominally homogeneous dephasing rates. The shifts (found to vary in rough proportion to the number of ${\mathrm{Eu}}^{3+}$ ions excited and to be as small as one part in ${10}^{12}$ ) were identified through their unique signature in specially designed photon-echo experiments. The effects reported may constitute a rather general complication in optical measurements of homogeneous relaxation rates in solids.Working on the $^{7}\mathrm{F}_{0}$${\mathrm{\ensuremath{-}}}^{5}$${\mathrm{D}}_{0}$ transition of ${\mathrm{Eu}}^{3+}$ in ${\mathrm{Y}}_{2}$${\mathrm{O}}_{3}$, we provide the first detailed characterization of excitation-induced shifts in optical transition frequencies and demonstrate their exaggeration of nominally homogeneous dephasing rates. The shifts (found to vary in rough proportion to the number of ${\mathrm{Eu}}^{3+}$ ions excited and to be as small as one part in ${10}^{12}$) were identified through their unique signature in specially designed photon-echo experiments. The effects reported may constitute a rather general complication in optical measurements of homogeneous relaxation rates in solids.

Physical Review LettersJul 3, 1989101 citations

Photon-echo attenuation in rare-earth-ion-doped crystals

Stefan B. Altner, G. Zumofen, Urs P. Wild +1 more

We study the optical properties of rare-earth-ion-doped inorganic crystals with an emphasis on the dependence of two-pulse photon echoes on the excitation density in the system. The experimental investigations concentrate on ${\mathrm{Pr}}^{3+}$ : ${\mathrm{Nd}}^{3+}$ : ${\mathrm{Eu}}^{3+}$ codoped ${\mathrm{Y}}_{2}$ Si ${\mathrm{O}}_{5}$ and YAl ${\mathrm{O}}_{3}$ crystals at low temperatures. With two pulses of one laser the echo is induced in one ion species and with a third, "scrambler" pulse of a second laser another species is excited. These scrambler excitations lead to a dephasing and thus to an echo attenuation which depends on the strength, frequency, and time of the scrambler pulse. The spectral sensitivity of the echo attenuation is used for a spectroscopic technique: "photon-echo attenuation spectroscopy." As a function of the delay time ${t}_{s}$ between the scrambler pulse and the onset of the two-pulse echo sequence the attenuation shows a very specific behavior dictated by the excitation-induced frequency shifts (EFS's). For ${t}_{s}$ between the two echo-inducing pulses the echo intensity is partially regained by the "dephasing-rephasing balancing" of the reversible EFS's. For the theoretical description a stochastic model is introduced and the dephasing by excitation-induced lattice vibrations and by EFS's are analyzed in detail. The present results are discussed in the light of previous experimental and theoretical investigations.We study the optical properties of rare-earth-ion-doped inorganic crystals with an emphasis on the dependence of two-pulse photon echoes on the excitation density in the system. The experimental investigations concentrate on ${\mathrm{Pr}}^{3+}$:${\mathrm{Nd}}^{3+}$:${\mathrm{Eu}}^{3+}$ codoped ${\mathrm{Y}}_{2}$Si${\mathrm{O}}_{5}$ and YAl${\mathrm{O}}_{3}$ crystals at low temperatures. With two pulses of one laser the echo is induced in one ion species and with a third, "scrambler" pulse of a second laser another species is excited. These scrambler excitations lead to a dephasing and thus to an echo attenuation which depends on the strength, frequency, and time of the scrambler pulse. The spectral sensitivity of the echo attenuation is used for a spectroscopic technique: "photon-echo attenuation spectroscopy." As a function of the delay time ${t}_{s}$ between the scrambler pulse and the onset of the two-pulse echo sequence the attenuation shows a very specific behavior dictated by the excitation-induced frequency shifts (EFS's). For ${t}_{s}$ between the two echo-inducing pulses the echo intensity is partially regained by the "dephasing-rephasing balancing" of the reversible EFS's. For the theoretical description a stochastic model is introduced and the dephasing by excitation-induced lattice vibrations and by EFS's are analyzed in detail. The present results are discussed in the light of previous experimental and theoretical investigations.

Physical review. B, Condensed matterDec 15, 199622 citations

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Physical Review LettersMar 4, 199624 citations

Intensity-dependent photon-echo relaxation in rare-earth-doped crystals

Stefan Kröll, E. Y. Xu, M. K. Kim +2 more

Photon-echo-relaxation measurements made on the $^{3}\mathrm{H}_{4}$ ${\mathrm{\ensuremath{-}}}^{3}$ ${\mathrm{P}}_{0}$ transition of 0.01 at. % ${\mathrm{Pr}}^{3+}$ :YAG (where YAG represents yttrium aluminum garnet), $^{3}\mathrm{H}_{4}$ ${\mathrm{\ensuremath{-}}}^{1}$ ${\mathrm{D}}_{2}$ transition in 0.1 at. % ${\mathrm{Pr}}^{3+}$ : ${\mathrm{YAlO}}_{3}$ , and $^{7}\mathrm{F}_{0}$ ${\mathrm{\ensuremath{-}}}^{5}$ ${\mathrm{D}}_{0}$ transition in 0.25 at. % ${\mathrm{Eu}}^{3+}$ : ${\mathrm{YAlO}}_{3}$ show that the photon-echo relaxation rate increases when the intensities of the excitation pulses are increased. Although a part of the relaxation-rate increase in ${\mathrm{Pr}}^{3+}$ :YAG may be attributed to an instantaneous spectral diffusion (ISD) in which the presence of excited neighboring ${\mathrm{Pr}}^{3+}$ ions change the local field and the absorption frequency of the rare-earth ions, our data deviate significantly from the ISD-model predictions. An additional intensity-dependent relaxation mechanism is required to explain the results.Photon-echo-relaxation measurements made on the $^{3}\mathrm{H}_{4}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{P}}_{0}$ transition of 0.01 at. % ${\mathrm{Pr}}^{3+}$:YAG (where YAG represents yttrium aluminum garnet), $^{3}\mathrm{H}_{4}$${\mathrm{\ensuremath{-}}}^{1}$${\mathrm{D}}_{2}$ transition in 0.1 at. % ${\mathrm{Pr}}^{3+}$:${\mathrm{YAlO}}_{3}$, and $^{7}\mathrm{F}_{0}$${\mathrm{\ensuremath{-}}}^{5}$${\mathrm{D}}_{0}$ transition in 0.25 at. % ${\mathrm{Eu}}^{3+}$:${\mathrm{YAlO}}_{3}$ show that the photon-echo relaxation rate increases when the intensities of the excitation pulses are increased. Although a part of the relaxation-rate increase in ${\mathrm{Pr}}^{3+}$:YAG may be attributed to an instantaneous spectral diffusion (ISD) in which the presence of excited neighboring ${\mathrm{Pr}}^{3+}$ ions change the local field and the absorption frequency of the rare-earth ions, our data deviate significantly from the ISD-model predictions. An additional intensity-dependent relaxation mechanism is required to explain the results.

Physical review. B, Condensed matterJun 1, 199033 citations

Laser-induced instantaneous spectral diffusion in Tb 3 + compounds as observed in photon-echo experiments

G. K. Liu, R. L. Cone

We have observed a significant ``instantaneous spectral diffusion'' phenomenon in photon-echo experiments on ${\mathrm{Tb}}^{3+}$ : ${\mathrm{LiYF}}_{4}$ . This laser-induced effect makes observed optical dephasing rates intensity dependent and can also contribute a frequency dependence to the measured rates. A change in the magnetic dipole-dipole interaction between ${\mathrm{Tb}}^{3+}$ echo ions and surrounding ${\mathrm{Tb}}^{3+}$ ions occurs when surrounding ions are excited. This causes an instantaneous shift in the optical frequency of the echo ion that lasts for ${\mathit{T}}_{1}$ \ensuremath{\sim}1 msec. Frequency shifts caused by the first excitation pulse have no effect on echo rephasing ( ${\mathit{T}}_{1}$ \ensuremath{\gg} ${\mathit{T}}_{2}$ ), but those caused by the second pulse prevent proper echo rephasing. A summary is given of other ion-lattice and ion-ion interactions that can cause similar laser-induced effects in a wide variety of insulating compounds. There is potential for probing the nature of inhomogeneous broadening.We have observed a significant ``instantaneous spectral diffusion'' phenomenon in photon-echo experiments on ${\mathrm{Tb}}^{3+}$:${\mathrm{LiYF}}_{4}$. This laser-induced effect makes observed optical dephasing rates intensity dependent and can also contribute a frequency dependence to the measured rates. A change in the magnetic dipole-dipole interaction between ${\mathrm{Tb}}^{3+}$ echo ions and surrounding ${\mathrm{Tb}}^{3+}$ ions occurs when surrounding ions are excited. This causes an instantaneous shift in the optical frequency of the echo ion that lasts for ${\mathit{T}}_{1}$\ensuremath{\sim}1 msec. Frequency shifts caused by the first excitation pulse have no effect on echo rephasing (${\mathit{T}}_{1}$\ensuremath{\gg}${\mathit{T}}_{2}$), but those caused by the second pulse prevent proper echo rephasing. A summary is given of other ion-lattice and ion-ion interactions that can cause similar laser-induced effects in a wide variety of insulating compounds. There is potential for probing the nature of inhomogeneous broadening.

Physical review. B, Condensed matterApr 1, 199061 citations

Photon-echo attenuation by dynamical processes in rare-earth-ion-doped crystals

Felix R. Graf, Alois Renn, G. Zumofen +1 more

We study the photon-echo attenuation by various dynamical processes in rare-earth-ion-doped crystals. The experimental investigations concentrate on a ${\mathrm{Pr}}^{3+}:{\mathrm{Eu}}^{3+}:{\mathrm{Nd}}^{3+}$ codoped ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal at low temperatures. Two-pulse photon-echo intensities are measured as a function of the pulse intensities when either the ${\mathrm{Pr}}^{3+}$ or the ${\mathrm{Eu}}^{3+}$ ions are excited. For the quantitative interpretation we consider primarily excitation-induced frequency shifts (EFS) by diagonal and off-diagonal interactions and show that for the systems under consideration EFS are dominated by diagonal interactions. The observed echo attenuation by EFS is compared with the predictions calculated from independent Stark-field measurements and reasonable agreement is obtained. The broadening by spin-ion interactions, by nonequilibrium phonons and the dependence of the echo attenuation on the frequency position in the inhomogeneously broadened band are further investigated.We study the photon-echo attenuation by various dynamical processes in rare-earth-ion-doped crystals. The experimental investigations concentrate on a ${\mathrm{Pr}}^{3+}:{\mathrm{Eu}}^{3+}:{\mathrm{Nd}}^{3+}$ codoped ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ crystal at low temperatures. Two-pulse photon-echo intensities are measured as a function of the pulse intensities when either the ${\mathrm{Pr}}^{3+}$ or the ${\mathrm{Eu}}^{3+}$ ions are excited. For the quantitative interpretation we consider primarily excitation-induced frequency shifts (EFS) by diagonal and off-diagonal interactions and show that for the systems under consideration EFS are dominated by diagonal interactions. The observed echo attenuation by EFS is compared with the predictions calculated from independent Stark-field measurements and reasonable agreement is obtained. The broadening by spin-ion interactions, by nonequilibrium phonons and the dependence of the echo attenuation on the frequency position in the inhomogeneously broadened band are further investigated.

Physical review. B, Condensed matterSep 1, 199858 citations

Working on the

^{7}\mathrm{F}_{0}

${\mathrm{\ensuremath{-}}}^{5}$

{\mathrm{D}}_{0}

transition of

{\mathrm{Eu}}^{3+}

{\mathrm{Y}}_{2}

{\mathrm{O}}_{3}

, we provide the first detailed characterization of excitation-induced shifts in optical transition frequencies and demonstrate their exaggeration of nominally homogeneous dephasing rates. The shifts (found to vary in rough proportion to the number of

{\mathrm{Eu}}^{3+}

ions excited and to be as small as one part in

{10}^{12}

) were identified through their unique signature in specially designed photon-echo experiments. The effects reported may constitute a rather general complication in optical measurements of homogeneous relaxation rates in solids.

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

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

{\mathrm{Eu}}^{3+}

codoped

{\mathrm{Y}}_{2}

{\mathrm{O}}_{5}

and YAl

{\mathrm{O}}_{3}

crystals at low temperatures. With two pulses of one laser the echo is induced in one ion species and with a third, "scrambler" pulse of a second laser another species is excited. These scrambler excitations lead to a dephasing and thus to an echo attenuation which depends on the strength, frequency, and time of the scrambler pulse. The spectral sensitivity of the echo attenuation is used for a spectroscopic technique: "photon-echo attenuation spectroscopy." As a function of the delay time

{t}_{s}

between the scrambler pulse and the onset of the two-pulse echo sequence the attenuation shows a very specific behavior dictated by the excitation-induced frequency shifts (EFS's). For

{t}_{s}

between the two echo-inducing pulses the echo intensity is partially regained by the "dephasing-rephasing balancing" of the reversible EFS's. For the theoretical description a stochastic model is introduced and the dephasing by excitation-induced lattice vibrations and by EFS's are analyzed in detail. The present results are discussed in the light of previous experimental and theoretical investigations.

Photon-echo-relaxation measurements made on the

^{3}\mathrm{H}_{4}

${\mathrm{\ensuremath{-}}}^{3}$

{\mathrm{P}}_{0}

transition of 0.01 at. %

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

:YAG (where YAG represents yttrium aluminum garnet),

^{3}\mathrm{H}_{4}

${\mathrm{\ensuremath{-}}}^{1}$

{\mathrm{D}}_{2}

transition in 0.1 at. %

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

{\mathrm{YAlO}}_{3}

, and

^{7}\mathrm{F}_{0}

${\mathrm{\ensuremath{-}}}^{5}$

{\mathrm{D}}_{0}

transition in 0.25 at. %

{\mathrm{Eu}}^{3+}

{\mathrm{YAlO}}_{3}

show that the photon-echo relaxation rate increases when the intensities of the excitation pulses are increased. Although a part of the relaxation-rate increase in

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

:YAG may be attributed to an instantaneous spectral diffusion (ISD) in which the presence of excited neighboring

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

ions change the local field and the absorption frequency of the rare-earth ions, our data deviate significantly from the ISD-model predictions. An additional intensity-dependent relaxation mechanism is required to explain the results.

We have observed a significant ``instantaneous spectral diffusion'' phenomenon in photon-echo experiments on

{\mathrm{Tb}}^{3+}

{\mathrm{LiYF}}_{4}

. This laser-induced effect makes observed optical dephasing rates intensity dependent and can also contribute a frequency dependence to the measured rates. A change in the magnetic dipole-dipole interaction between

{\mathrm{Tb}}^{3+}

echo ions and surrounding

{\mathrm{Tb}}^{3+}

ions occurs when surrounding ions are excited. This causes an instantaneous shift in the optical frequency of the echo ion that lasts for

{\mathit{T}}_{1}

\ensuremath{\sim}1 msec. Frequency shifts caused by the first excitation pulse have no effect on echo rephasing (

{\mathit{T}}_{1}

\ensuremath{\gg}

{\mathit{T}}_{2}

), but those caused by the second pulse prevent proper echo rephasing. A summary is given of other ion-lattice and ion-ion interactions that can cause similar laser-induced effects in a wide variety of insulating compounds. There is potential for probing the nature of inhomogeneous broadening.

We study the photon-echo attenuation by various dynamical processes in rare-earth-ion-doped crystals. The experimental investigations concentrate on a

{\mathrm{Pr}}^{3+}:{\mathrm{Eu}}^{3+}:{\mathrm{Nd}}^{3+}

codoped

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

crystal at low temperatures. Two-pulse photon-echo intensities are measured as a function of the pulse intensities when either the

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

or the

{\mathrm{Eu}}^{3+}

ions are excited. For the quantitative interpretation we consider primarily excitation-induced frequency shifts (EFS) by diagonal and off-diagonal interactions and show that for the systems under consideration EFS are dominated by diagonal interactions. The observed echo attenuation by EFS is compared with the predictions calculated from independent Stark-field measurements and reasonable agreement is obtained. The broadening by spin-ion interactions, by nonequilibrium phonons and the dependence of the echo attenuation on the frequency position in the inhomogeneously broadened band are further investigated.