Optical dephasing in disordered and nanoscale crystalline materials

Two-pulse photon-echo measurements were made on the $^{7}$ ${\mathit{F}}_{0}$ ${\mathrm{\ensuremath{\leftrightarrows}}}^{5}$ ${\mathit{D}}_{0}$ optical transition in a number of crystalline samples of ${\mathrm{Y}}_{2}$ ${\mathrm{O}}_{3}$ : ${\mathrm{Eu}}^{3+}$ prepared by three different crystal-growth techniques. For crystals prepared by a laser-heated pedestal growth or arc-imaging furnace process, we report the observation of an additional sample-dependent contribution to the optical dephasing in comparison with a crystal grown by flame fusion. The dephasing rate 1/ ${\mathit{T}}_{\mathit{m}}$ at 1.4 K is up to two orders of magnitude faster than that previously reported for the flame-fusion-grown crystal, and is uncorrelated with concentration. Measurements up to 14 K show that 1/ ${\mathit{T}}_{\mathit{m}}$ increases linearly with temperature, in contrast to the expected ${\mathit{T}}^{7}$ behavior due to a two-phonon Raman process. The linear temperature dependence is similar to that seen in glasses and disordered crystalline systems, suggesting the presence of disorder in the samples with more rapid dephasing. The crystals were examined by x-ray diffraction, excitation spectroscopy, and near-field optical microscopy to provide information on the nature of the disorder. The effect of annealing on the crystal dynamics is also investigated.Two-pulse photon-echo measurements were made on the $^{7}$${\mathit{F}}_{0}$${\mathrm{\ensuremath{\leftrightarrows}}}^{5}$${\mathit{D}}_{0}$ optical transition in a number of crystalline samples of ${\mathrm{Y}}_{2}$${\mathrm{O}}_{3}$:${\mathrm{Eu}}^{3+}$ prepared by three different crystal-growth techniques. For crystals prepared by a laser-heated pedestal growth or arc-imaging furnace process, we report the observation of an additional sample-dependent contribution to the optical dephasing in comparison with a crystal grown by flame fusion. The dephasing rate 1/${\mathit{T}}_{\mathit{m}}$ at 1.4 K is up to two orders of magnitude faster than that previously reported for the flame-fusion-grown crystal, and is uncorrelated with concentration. Measurements up to 14 K show that 1/${\mathit{T}}_{\mathit{m}}$ increases linearly with temperature, in contrast to the expected ${\mathit{T}}^{7}$ behavior due to a two-phonon Raman process. The linear temperature dependence is similar to that seen in glasses and disordered crystalline systems, suggesting the presence of disorder in the samples with more rapid dephasing. The crystals were examined by x-ray diffraction, excitation spectroscopy, and near-field optical microscopy to provide information on the nature of the disorder. The effect of annealing on the crystal dynamics is also investigated.

Physical review. B, Condensed matterMar 1, 199455 citations

Subkilohertz optical homogeneous linewidth and dephasing mechanisms in Er3+ : Y2O3 ceramics

Rikuto Fukumori, Yizhong Huang, Jun Mo Yang +2 more

Rare-earth dopants in solids are conducive of sharp optical transitions and long spin coherence at cryogenic temperatures. While superb coherences are routine in high-quality bulk crystals, the more versatile materials such as rare-earth doped nanoparticles and ceramics have suffered from excessive decoherence due to disorder. This work reports a surprisingly narrow linewidth of Er in Y ${}_{2}$ O ${}_{3}$ ceramics made with industry-standard synthesis technique, putting it on par with the best single crystalline counterpart. The ultranarrow linewidth also helps clarify decoherence pathways within the matrix.Rare-earth dopants in solids are conducive of sharp optical transitions and long spin coherence at cryogenic temperatures. While superb coherences are routine in high-quality bulk crystals, the more versatile materials such as rare-earth doped nanoparticles and ceramics have suffered from excessive decoherence due to disorder. This work reports a surprisingly narrow linewidth of Er in Y${}_{2}$O${}_{3}$ ceramics made with industry-standard synthesis technique, putting it on par with the best single crystalline counterpart. The ultranarrow linewidth also helps clarify decoherence pathways within the matrix.

arXiv:1911.05058Physical review. B./Physical review. BJun 8, 202032 citations

Low Temperature Optical Dephasing of Rare Earth Ions by Tunneling Systems in Glass

Matthijs M. Broer

Optical dephasing of paramagnetic ions and molecules in organic and inorganic amorphous solids at low temperatures (≲100K) is characterized by unusual temperature dependences and enhanced relaxation rates compared to crystalline systems1. For a large variety of impurity-host combinations the dephasing rate has been found to follow a Tm temperature dependence with m approximately 2. Several theories have attempted to explain this behavior by assuming interactions between the optical center, phonons, and atomic tunneling systems. However, the role of the intrinsic disorder in optical dephasing in these systems is not clearly understood.Optical dephasing of paramagnetic ions and molecules in organic and inorganic amorphous solids at low temperatures (≲100K) is characterized by unusual temperature dependences and enhanced relaxation rates compared to crystalline systems1. For a large variety of impurity-host combinations the dephasing rate has been found to follow a Tm temperature dependence with m approximately 2. Several theories have attempted to explain this behavior by assuming interactions between the optical center, phonons, and atomic tunneling systems. However, the role of the intrinsic disorder in optical dephasing in these systems is not clearly understood.

International Conference on Luminescence - 1984Jan 1, 19841 citation

Two-pulse photon-echo measurements were made on the

^{7}

{\mathit{F}}_{0}

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

{\mathit{D}}_{0}

optical transition in a number of crystalline samples of

{\mathrm{Y}}_{2}

{\mathrm{O}}_{3}

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

prepared by three different crystal-growth techniques. For crystals prepared by a laser-heated pedestal growth or arc-imaging furnace process, we report the observation of an additional sample-dependent contribution to the optical dephasing in comparison with a crystal grown by flame fusion. The dephasing rate 1/

{\mathit{T}}_{\mathit{m}}

at 1.4 K is up to two orders of magnitude faster than that previously reported for the flame-fusion-grown crystal, and is uncorrelated with concentration. Measurements up to 14 K show that 1/

{\mathit{T}}_{\mathit{m}}

increases linearly with temperature, in contrast to the expected

{\mathit{T}}^{7}

behavior due to a two-phonon Raman process. The linear temperature dependence is similar to that seen in glasses and disordered crystalline systems, suggesting the presence of disorder in the samples with more rapid dephasing. The crystals were examined by x-ray diffraction, excitation spectroscopy, and near-field optical microscopy to provide information on the nature of the disorder. The effect of annealing on the crystal dynamics is also investigated.

{}_{2}

{}_{3}

ceramics made with industry-standard synthesis technique, putting it on par with the best single crystalline counterpart. The ultranarrow linewidth also helps clarify decoherence pathways within the matrix.