Physical Review Letters

Observation of Simultaneous Excitation of the Coupled Cr3+ Ions to the Eg2 States in LaAl O3 : Cr3+

Jan P. van der Ziel

Published Mar 29, 1971• 11 citations

Abstract

Transitions to the states of ${\mathrm{Cr}}^{3+}$ pairs where both ions are excited to the $^{2}E_{g}$ levels have been observed in LaAl${\mathrm{O}}_{3}$:${\mathrm{Cr}}^{3+}$. Of the predicted eight pair levels, three of the $S=0$ and one of the $S=1$ levels have definitely been identified at approximately twice the $^{2}E_{g}$ energy absorption. The remaining transitions either are obscured by the strong vibronic spectrum or are very weak. The polarization of the lines agrees with a model based on the mechanism of exchange-induced electric dipole moment.

DOI: 10.1103/physrevlett.26.766

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Cooperative Absorption and Luminescence in Cr3+ -Doped EuAl O3

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Physical Review Letters

Observation of Simultaneous Excitation of the Coupled Cr3+ Ions to the Eg2 States in LaAl O3 : Cr3+

Jan P. van der Ziel

Published Mar 29, 1971• 11 citations

Publisher

Abstract

Transitions to the states of

{\mathrm{Cr}}^{3+}

pairs where both ions are excited to the

^{2}E_{g}

levels have been observed in LaAl

{\mathrm{O}}_{3}

{\mathrm{Cr}}^{3+}

. Of the predicted eight pair levels, three of the

S=0

and one of the

S=1

levels have definitely been identified at approximately twice the

^{2}E_{g}

energy absorption. The remaining transitions either are obscured by the strong vibronic spectrum or are very weak. The polarization of the lines agrees with a model based on the mechanism of exchange-induced electric dipole moment.

DOI: 10.1103/physrevlett.26.766

Related papers

Cooperative Absorption and Luminescence in Cr3+ -Doped EuAl O3

Jan P. van der Ziel, LeGrand G. Van Uitert

Absorption and emission involving exchange-coupled nearest-neighbor ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Eu}}^{3+}$ ions have been observed in ${\mathrm{Cr}}^{3+}$ -doped EuAl ${\mathrm{O}}_{3}$ at the sum of the chromium $^{2}E_{g}$ and europium $^{7}F_{1}$ energies. Weak absorption at the difference energy has also been observed. The latter is the inverse of the previously studied europium terminated chromium emission. The intensities of the ${\mathrm{Eu}}^{3+}$ sideband transitions vary with the strength of the exchange-induced electric dipole moment.Absorption and emission involving exchange-coupled nearest-neighbor ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Eu}}^{3+}$ ions have been observed in ${\mathrm{Cr}}^{3+}$-doped EuAl${\mathrm{O}}_{3}$ at the sum of the chromium $^{2}E_{g}$ and europium $^{7}F_{1}$ energies. Weak absorption at the difference energy has also been observed. The latter is the inverse of the previously studied europium terminated chromium emission. The intensities of the ${\mathrm{Eu}}^{3+}$ sideband transitions vary with the strength of the exchange-induced electric dipole moment.

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Absorption Spectrum of Optically Pumped Al2 O3 : Cr3+

Huang Jin, Henry W. Moos

The absorption cross sections of the ${\mathrm{Cr}}^{3+}$ ion in the metastable states $^{2}E (\overline{E} \mathrm{and} 2\overline{A})$ of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.The absorption cross sections of the ${\mathrm{Cr}}^{3+}$ ion in the metastable states $^{2}E (\overline{E} \mathrm{and} 2\overline{A})$ of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.

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Transition Probabilities for the Excited State dε3Γ32 of Cr3+

Albert M. Clogston

In recent experiments Geschwind has observed transitions between the Zeeman components of the excited metastable state $d{\ensuremath{\epsilon}}^{3}^{2}\ensuremath{\Gamma}_{3}$ of trivalent chromium present as a dilute impurity in ${\mathrm{Al}}_{2}$ ${\mathrm{O}}_{3}$ . In first order the transitions are forbidden. In third order a number of processes give rise to a transition probability and predict ${g}_{\ensuremath{\perp}}=0.1$, consistent with the experimental observations. The magnetic moment associated with the transition is shown to rotate opposite to the usual sense.In recent experiments Geschwind has observed transitions between the Zeeman components of the excited metastable state $d{\ensuremath{\epsilon}}^{3}^{2}\ensuremath{\Gamma}_{3}$ of trivalent chromium present as a dilute impurity in ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$. In first order the transitions are forbidden. In third order a number of processes give rise to a transition probability and predict ${g}_{\ensuremath{\perp}}=0.1$, consistent with the experimental observations. The magnetic moment associated with the transition is shown to rotate opposite to the usual sense.

Physical ReviewJun 1, 196015 citations

Photon-assisted off-resonance energy transfer between Cr3+ and Gd3+ in GdAlO3

José Luciano Miranda Duarte, Jarbas Caiado de Castro

We report here a clear observation of photon-assisted off-resonance energy transfer. Our experiment was carried out in crystals of gadolinium aluminate ( ${\mathrm{GdAlO}}_{3}$ ) doped with chromium ions ( ${\mathrm{Cr}}^{3+}$ ). The observed phenomenon consists of the energy transfer from a ${\mathrm{Cr}}^{3+}$ ion, previously excited to the $^{2}$ E state (located at about 13.770 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ above the ground state), to a neighbor ${\mathrm{Gd}}^{3+}$ ion (which has the first excited state located at about 31.840 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$), with the simultaneous absorption of a photon that energy matches exactly the difference between the gadolinium excited-state energy and the energy supplied by the chromium ion.We report here a clear observation of photon-assisted off-resonance energy transfer. Our experiment was carried out in crystals of gadolinium aluminate (${\mathrm{GdAlO}}_{3}$) doped with chromium ions (${\mathrm{Cr}}^{3+}$). The observed phenomenon consists of the energy transfer from a ${\mathrm{Cr}}^{3+}$ ion, previously excited to the $^{2}$E state (located at about 13.770 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ above the ground state), to a neighbor ${\mathrm{Gd}}^{3+}$ ion (which has the first excited state located at about 31.840 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$), with the simultaneous absorption of a photon that energy matches exactly the difference between the gadolinium excited-state energy and the energy supplied by the chromium ion.

Physical review. B, Condensed matterSep 1, 19922 citations

Transitions to the states of

{\mathrm{Cr}}^{3+}

pairs where both ions are excited to the

^{2}E_{g}

levels have been observed in LaAl

{\mathrm{O}}_{3}

{\mathrm{Cr}}^{3+}

. Of the predicted eight pair levels, three of the

S=0

and one of the

S=1

levels have definitely been identified at approximately twice the

^{2}E_{g}

Absorption and emission involving exchange-coupled nearest-neighbor

{\mathrm{Cr}}^{3+}

and

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

ions have been observed in

{\mathrm{Cr}}^{3+}

-doped EuAl

{\mathrm{O}}_{3}

at the sum of the chromium

^{2}E_{g}

and europium

^{7}F_{1}

energies. Weak absorption at the difference energy has also been observed. The latter is the inverse of the previously studied europium terminated chromium emission. The intensities of the

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

sideband transitions vary with the strength of the exchange-induced electric dipole moment.

The absorption cross sections of the

{\mathrm{Cr}}^{3+}

ion in the metastable states

^{2}E (\overline{E} \mathrm{and} 2\overline{A})

of lightly doped ruby (\ensuremath{\sim}0.01%) have been measured as a function of polarization at temperatures of 30, 105, and 296\ifmmode^\circ\else\textdegree\fi{}K in the region from 2300 to 7000 \AA{}. The lifetime of these states was measured by observing the decay rate of the excited-state absorption, and agreed with the value of the measured fluorescence decay rate at various temperatures. The population of the excited states was measured by the change of the area under the first two vibronic sidebands at low temperatures. At room temperature the population was measured by the change of transmitted intensity of a ruby laser.

{\mathrm{Al}}_{2}

{\mathrm{O}}_{3}

. In first order the transitions are forbidden. In third order a number of processes give rise to a transition probability and predict ${g}_{\ensuremath{\perp}}=0.1$, consistent with the experimental observations. The magnetic moment associated with the transition is shown to rotate opposite to the usual sense.

We report here a clear observation of photon-assisted off-resonance energy transfer. Our experiment was carried out in crystals of gadolinium aluminate (

{\mathrm{GdAlO}}_{3}

) doped with chromium ions (

{\mathrm{Cr}}^{3+}

). The observed phenomenon consists of the energy transfer from a

{\mathrm{Cr}}^{3+}

ion, previously excited to the

^{2}

E state (located at about 13.770 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ above the ground state), to a neighbor

{\mathrm{Gd}}^{3+}

ion (which has the first excited state located at about 31.840 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$), with the simultaneous absorption of a photon that energy matches exactly the difference between the gadolinium excited-state energy and the energy supplied by the chromium ion.