Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics C Solid State Physics

Spatial energy transfer: Cr3+clustering around vacancies in MgO crystal

A. Boyrivent, Maurizio Ferrari, Eugène Duval, André Monteil

Published Jun 20, 1986• 7 citations
Publisher

Abstract

The optical energy transfer between Cr 3+ ions from cubic centres to tetragonal centres is measured. Transfer is observed only when the donor is very close to the acceptor and the measured transfer times are relatively short ( approximately 100 mu s). The tetragonal acceptors are Cr 3+ -ion pairs which form different triads with the donor. It is deduced that transfer to rhombic sites is also rapid only from very close cubic centres. The shortness of the transfer times explains why a spin memory is observed during the energy transfer from cubic to rhombic centres. The localisation of optical excitation in triads is due to the presence of charge-compensating Mg 2+ vacancies and the inefficiency of the dipole-dipole interaction.

DOI
10.1088/0022-3719/19/17/019

Related papers

Phase Coherence in the 2E state of Cr3+ ions in MgO detected via ODMR

B. Henderson

The coupling between the Zeeman sublevels of an atom by a resonant microwave magnetic field also induces a phase coherence between the states. The effect is equivalent to the precession at the Zeeman frequency of a transverse magnetic moment about the static magnetic, and is manifest as a modulation of the circularly polarized emission at the Zeeman frequency. We have investigated such phase coherence in the 2E excited state of Cr3+ ions occupying sites of both cubic and tetragonal symmetry in magnesium oxide, MgO. The experiments were carried out at 1.6K, in the X-band frequency range (ν ~ 9.5 GHz) with the magnetic field parallel to the crystal [111] direction. In this orientation the optically detected magnetic resonance spectra from Cr3+ ions in cubic and tetragonal symmetry sites are well-separated in magnetic field. In addition all three resonances from the mutually orthogonal tetragonal species occur at the same magnetic field. The purpose of this geometry is to eliminate cross-relaxation between cubic and tetragonal sites.

International Conference on Luminescence - 1984•Jan 1, 1984•0 citations

Energy transfer and rate equations—application to ruby

Johann Heber

Abstract Atomistic rate equations are represented for the transfer of optical excitation energy between donor and acceptor ions in ionic crystals. The physical assumptions which are necessary to deduce the phenomenological collective rate equations from the atomistic ones are specified. Time resolved measurements of the energy transfer from isolated Cr3+ ions to Cr3+ pairs in ruby are discussed. It is shown that, contrary to the present ideas, the collective rate equations cannot be applied in this case.

physica status solidi (b)•Jan 1, 1970•13 citations

Line broadening studies for Cr3+pairs and single ions in different oxide lattices

A.P. Vink, M. A. de Bruin, Andries Meijerink

The electron-phonon coupling for Cr 3+ in different oxide host lattices (MgO, α-Al 2 O 3 and LaAlO 3 ) was probed by performing temperature dependent line broadening measurements for zero-phonon emission lines of single ions and exchange coupled pairs. No differences in electron-phonon coupling were found comparing the results for pairs and single ions in α-Al 2 O 3 (3NN and 4NN pairs) and LaAlO 3 (NN pairs). In Cr 3+ doped MgO (Cr 3+ -V Mg -Cr 3+ pairs), it was found that the electron-phonon coupling strength parameter is larger for the pairs than for the isolated Cr 3+ ions. This is probably due to changes in the surroundings of Cr 3+ by local charge compensation by a magnesium vacancy, and not to interaction between the Cr 3+ ions.

Journal of Physics Condensed Matter•Sep 19, 2000•18 citations

Mechanisms for three-centre energy pooling in lanthanide doped crystals

Robert D. Jenkins, Davıd L. Andrews

Summary form only given. The migration of excitation energy within dielectric crystals doped with lanthanide ions is a rich area for the study of mechanisms involving both conventional pairwise resonance energy transfer and more complex many-body effects. Within the framework of molecular quantum electrodynamics, we present a delineation of systems undergoing simultaneous transfer from two pre-excited donor ions to a single ground-state acceptor, termed three-centre energy pooling. Calculations lead to the identification of two competing mechanisms of transfer co-existing in each system-one cooperative pathway where the excitation is transferred directly to the acceptor from both donors, alongside an accretive mechanism where the excitation energy of one donor is accrued by a second, with net transfer to the acceptor ensuing.

Conference on Lasers and Electro-Optics•Aug 29, 2005•0 citations

Cooperative Quenching Energy Transfer in La1−xCexF3 Crystal

Tasoltan T. Basiev, Maxim E. Doroshenko, В. В. Осико

A new phenomena of nonradiative cooperative energy transfer from optically excited single Nd3+ ion to the cooperative acceptor formed by a pair of Ce3+ ions and from single excited Er3+ ion simultaneously to three Ce3+ ions acting as a nonlinear cooperative acceptor was observed by measuring the concentrational quenching of donor ions fluorescence in solid solution of La1−xCexF3.

Advanced Solid-State Lasers•Jan 1, 2000•1 citation

Optically pump-induced athermal and nonresonant refractive index changes in the reference Cr-doped laser materials: Cr:GSGG and ruby

Thomas Godin, R. Moncorgé, J.L. Doualan +4 more

The refractive index of most ion-doped materials increases with the excited state population. This effect was studied in many laser materials, particularly those doped with Cr3+ and rare earth ions, using several techniques, such as interferometry, wave mixing, and Z-scans. This refractive index variation is athermal (has an electronic origin) and is associated with the difference in the polarizabilites of the Cr3+ ion in its excited and ground states, Δαp. The Cr3+ optical transitions in the visible domain are electric-dipole forbidden, and they have low oscillator strengths. Therefore, the major contribution to Δαp has been assigned to allowed transitions to charge transfer bands (CTBs) in the UV with strengths ∼3 orders of magnitude higher. Although this CTB model qualitatively explains the main observations, it was never quantitatively tested. In order to further investigate the physical origin of Δαp in Cr3+-doped crystals, excited state absorption (ESA) and Z-scan measurements were thus performed in Cr:Al2O3 (ruby) and Cr:GSGG. Cr:GSGG was selected because of the proximity of its E2 and T24 emitting levels, and thus the possibility to explore the role of the spin selection rule in the ESA spectra and the resulting variations in polarizability by comparing low and room temperature data, which were never reported before. On the other hand, Cr:Al2O3 (ruby) was selected because it is the only crystal for which it is possible to obtain CTB absorption data from both ground and excited states, and thus for which it is possible to check the CTB model more accurately. Thanks to these more accurate and more complete data, we came to the first conclusion that the spin selection rule does not play any significant role in the variation of the polarizability with the E2–T24 energy mismatch. We also discovered that using the CTB model in the case of ruby would lead to a negative Δαp value, which is contrary to all refractive index variation (including Z-scan) measurements.

Journal of the Optical Society of America B•Apr 23, 2012•22 citations
The optical energy transfer between Cr 3+ ions from cubic centres to tetragonal centres is measured. Transfer is observed only when the donor is very close to the acceptor and the measured transfer times are relatively short ( approximately 100 mu s). The tetragonal acceptors are Cr 3+ -ion pairs which form different triads with the donor. It is deduced that transfer to rhombic sites is also rapid only from very close cubic centres. The shortness of the transfer times explains why a spin memory is observed during the energy transfer from cubic to rhombic centres. The localisation of optical excitation in triads is due to the presence of charge-compensating Mg 2+ vacancies and the inefficiency of the dipole-dipole interaction.
The coupling between the Zeeman sublevels of an atom by a resonant microwave magnetic field also induces a phase coherence between the states. The effect is equivalent to the precession at the Zeeman frequency of a transverse magnetic moment about the static magnetic, and is manifest as a modulation of the circularly polarized emission at the Zeeman frequency. We have investigated such phase coherence in the 2E excited state of Cr3+ ions occupying sites of both cubic and tetragonal symmetry in magnesium oxide, MgO. The experiments were carried out at 1.6K, in the X-band frequency range (ν ~ 9.5 GHz) with the magnetic field parallel to the crystal [111] direction. In this orientation the optically detected magnetic resonance spectra from Cr3+ ions in cubic and tetragonal symmetry sites are well-separated in magnetic field. In addition all three resonances from the mutually orthogonal tetragonal species occur at the same magnetic field. The purpose of this geometry is to eliminate cross-relaxation between cubic and tetragonal sites.
Abstract Atomistic rate equations are represented for the transfer of optical excitation energy between donor and acceptor ions in ionic crystals. The physical assumptions which are necessary to deduce the phenomenological collective rate equations from the atomistic ones are specified. Time resolved measurements of the energy transfer from isolated Cr3+ ions to Cr3+ pairs in ruby are discussed. It is shown that, contrary to the present ideas, the collective rate equations cannot be applied in this case.
The electron-phonon coupling for Cr 3+ in different oxide host lattices (MgO, α-Al 2 O 3 and LaAlO 3 ) was probed by performing temperature dependent line broadening measurements for zero-phonon emission lines of single ions and exchange coupled pairs. No differences in electron-phonon coupling were found comparing the results for pairs and single ions in α-Al 2 O 3 (3NN and 4NN pairs) and LaAlO 3 (NN pairs). In Cr 3+ doped MgO (Cr 3+ -V Mg -Cr 3+ pairs), it was found that the electron-phonon coupling strength parameter is larger for the pairs than for the isolated Cr 3+ ions. This is probably due to changes in the surroundings of Cr 3+ by local charge compensation by a magnesium vacancy, and not to interaction between the Cr 3+ ions.
Summary form only given. The migration of excitation energy within dielectric crystals doped with lanthanide ions is a rich area for the study of mechanisms involving both conventional pairwise resonance energy transfer and more complex many-body effects. Within the framework of molecular quantum electrodynamics, we present a delineation of systems undergoing simultaneous transfer from two pre-excited donor ions to a single ground-state acceptor, termed three-centre energy pooling. Calculations lead to the identification of two competing mechanisms of transfer co-existing in each system-one cooperative pathway where the excitation is transferred directly to the acceptor from both donors, alongside an accretive mechanism where the excitation energy of one donor is accrued by a second, with net transfer to the acceptor ensuing.
The refractive index of most ion-doped materials increases with the excited state population. This effect was studied in many laser materials, particularly those doped with Cr3+ and rare earth ions, using several techniques, such as interferometry, wave mixing, and Z-scans. This refractive index variation is athermal (has an electronic origin) and is associated with the difference in the polarizabilites of the Cr3+ ion in its excited and ground states, Δαp. The Cr3+ optical transitions in the visible domain are electric-dipole forbidden, and they have low oscillator strengths. Therefore, the major contribution to Δαp has been assigned to allowed transitions to charge transfer bands (CTBs) in the UV with strengths ∼3 orders of magnitude higher. Although this CTB model qualitatively explains the main observations, it was never quantitatively tested. In order to further investigate the physical origin of Δαp in Cr3+-doped crystals, excited state absorption (ESA) and Z-scan measurements were thus performed in Cr:Al2O3 (ruby) and Cr:GSGG. Cr:GSGG was selected because of the proximity of its E2 and T24 emitting levels, and thus the possibility to explore the role of the spin selection rule in the ESA spectra and the resulting variations in polarizability by comparing low and room temperature data, which were never reported before. On the other hand, Cr:Al2O3 (ruby) was selected because it is the only crystal for which it is possible to obtain CTB absorption data from both ground and excited states, and thus for which it is possible to check the CTB model more accurately. Thanks to these more accurate and more complete data, we came to the first conclusion that the spin selection rule does not play any significant role in the variation of the polarizability with the E2–T24 energy mismatch. We also discovered that using the CTB model in the case of ruby would lead to a negative Δαp value, which is contrary to all refractive index variation (including Z-scan) measurements.