Energy Transfer Under Strong Pumping in High-Concentration Rare Earth Doped Laser Crystals

The enhanced laser cooling performance of rare-earth-ion-doped nanocrystalline powders is predicted, compared to the bulk material, using ${\mathrm{Yb}}^{3+}:{\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ as the model material. This is achieved by enhancing the off-resonance, phonon-assisted absorption, which is proportional to the three factors considered in this paper: the dopant concentration, the pumping field energy, and the excitation coefficient. Using the energy transfer theory for concentration quenching, the optimum concentration corresponding to the maximum cooling power is found to be considerably larger than the currently used value, suggesting noticeable enhancement effects for laser cooling. The pumping field energy is enhanced in random nanopowders compared with bulk crystals under the same irradiation, due to the multiple scattering of photons. Photons are thus localized in the medium and do not propagate through, increasing the photon absorption of the pumping beam (and it is shown that the reabsorption of the fluorescence is negligible). Using molecular dynamics simulations, the phonon density of states (DOS) of the nanopowder is calculated, and found to have broadened modes, and extended small tails at low and high frequencies. The second-order electronic transition rate for the anti-Stokes luminescence is calculated using the Fermi golden rule, which includes the influence of this phonon DOS, and is shown to have enhancement effects on the laser cooling efficiency using nanopowders. It is finally concluded that these three enhancement mechanisms are essentially to increase the population of the three participating carriers (electron, photon, and phonon) in the interacting volume, and this also points out directions for enhancing laser cooling performance in bulk materials.The enhanced laser cooling performance of rare-earth-ion-doped nanocrystalline powders is predicted, compared to the bulk material, using ${\mathrm{Yb}}^{3+}:{\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ as the model material. This is achieved by enhancing the off-resonance, phonon-assisted absorption, which is proportional to the three factors considered in this paper: the dopant concentration, the pumping field energy, and the excitation coefficient. Using the energy transfer theory for concentration quenching, the optimum concentration corresponding to the maximum cooling power is found to be considerably larger than the currently used value, suggesting noticeable enhancement effects for laser cooling. The pumping field energy is enhanced in random nanopowders compared with bulk crystals under the same irradiation, due to the multiple scattering of photons. Photons are thus localized in the medium and do not propagate through, increasing the photon absorption of the pumping beam (and it is shown that the reabsorption of the fluorescence is negligible). Using molecular dynamics simulations, the phonon density of states (DOS) of the nanopowder is calculated, and found to have broadened modes, and extended small tails at low and high frequencies. The second-order electronic transition rate for the anti-Stokes luminescence is calculated using the Fermi golden rule, which includes the influence of this phonon DOS, and is shown to have enhancement effects on the laser cooling efficiency using nanopowders. It is finally concluded that these three enhancement mechanisms are essentially to increase the population of the three participating carriers (electron, photon, and phonon) in the interacting volume, and this also points out directions for enhancing laser cooling performance in bulk materials.

Physical Review BApr 21, 200672 citations

Energy transfer in stoichiometric rare-earth crystals

Richard C. Powell, Walter K. Zwicker

laseJan 1, 19820 citations

Analysis of intrinsic optical bistability in Tm-doped laser-related crystals

Mikhail A. Noginov, Martina Vondrova, Daniel Casimir

We predict and theoretically study intrinsic optical bistability (IOB) mediated by nonlinear energy transfer processes in rare-earth-doped laser-related crystals. In particular, we investigate Tm-Ho and Tm-Yb systems, in which avalanche pumping is overimposed by energy transfer up-conversion. We predict that IOB can be experimentally observed in $(\mathrm{T}\mathrm{m},\mathrm{Y}\mathrm{b}):{\mathrm{BaY}}_{2}{\mathrm{F}}_{8}$ crystals in a wide range of experimentally achievable parameters.We predict and theoretically study intrinsic optical bistability (IOB) mediated by nonlinear energy transfer processes in rare-earth-doped laser-related crystals. In particular, we investigate Tm-Ho and Tm-Yb systems, in which avalanche pumping is overimposed by energy transfer up-conversion. We predict that IOB can be experimentally observed in $(\mathrm{T}\mathrm{m},\mathrm{Y}\mathrm{b}):{\mathrm{BaY}}_{2}{\mathrm{F}}_{8}$ crystals in a wide range of experimentally achievable parameters.

Physical review. B, Condensed matterNov 25, 200314 citations

Investigation of the Mechanism of the Elementary Act of Excitation-energy Transfer Between Rare-earth Ions in Crystals

Yu. K. Voron’ko, В. В. Осико, Alexander M. Prokhorov +1 more

Journal of Experimental and Theoretical PhysicsJan 1, 19711 citation

High-connectivity quantum processor nodes using single-ion qubits in rare-earth-ion-doped crystals

Adam Kinos, Lars Rippe, Diana Serrano +2 more

We present two protocols for constructing quantum processor nodes in randomly doped rare-earth-ion crystals and analyze their properties. By varying the doping concentration and the accessible laser tunability, the processor nodes can contain anywhere from only a few tens to almost 1000 qubits. Furthermore, the average number of qubits each qubit can interact with, denoted by the connectivity, can be partly tailored to lie between just a few and roughly 100. We also study how a limited tunability of the laser affects the results and conclude that a tuning range of 100 GHz limits the results to roughly 100 qubits with around 50 connections per qubit on average. In order to construct an even larger processor, the vision is that several of these quantum processor nodes should be connected to each other in a multinode architecture via, e.g., optical interfaces or flying qubits in the form of light. Our results are encouraging for establishing the rare-earth-ion-based systems as a quantum computing platform with strong potential and can serve to focus the efforts within the field.We present two protocols for constructing quantum processor nodes in randomly doped rare-earth-ion crystals and analyze their properties. By varying the doping concentration and the accessible laser tunability, the processor nodes can contain anywhere from only a few tens to almost 1000 qubits. Furthermore, the average number of qubits each qubit can interact with, denoted by the connectivity, can be partly tailored to lie between just a few and roughly 100. We also study how a limited tunability of the laser affects the results and conclude that a tuning range of 100 GHz limits the results to roughly 100 qubits with around 50 connections per qubit on average. In order to construct an even larger processor, the vision is that several of these quantum processor nodes should be connected to each other in a multinode architecture via, e.g., optical interfaces or flying qubits in the form of light. Our results are encouraging for establishing the rare-earth-ion-based systems as a quantum computing platform with strong potential and can serve to focus the efforts within the field.

arXiv:2111.09016Physical Review AMar 4, 202219 citations

Novel mechanism for energy transfer between rare earth ions

W. Stręk

Journal of LuminescenceDec 1, 19840 citations

The enhanced laser cooling performance of rare-earth-ion-doped nanocrystalline powders is predicted, compared to the bulk material, using

{\mathrm{Yb}}^{3+}:{\mathrm{Y}}_{2}{\mathrm{O}}_{3}

as the model material. This is achieved by enhancing the off-resonance, phonon-assisted absorption, which is proportional to the three factors considered in this paper: the dopant concentration, the pumping field energy, and the excitation coefficient. Using the energy transfer theory for concentration quenching, the optimum concentration corresponding to the maximum cooling power is found to be considerably larger than the currently used value, suggesting noticeable enhancement effects for laser cooling. The pumping field energy is enhanced in random nanopowders compared with bulk crystals under the same irradiation, due to the multiple scattering of photons. Photons are thus localized in the medium and do not propagate through, increasing the photon absorption of the pumping beam (and it is shown that the reabsorption of the fluorescence is negligible). Using molecular dynamics simulations, the phonon density of states (DOS) of the nanopowder is calculated, and found to have broadened modes, and extended small tails at low and high frequencies. The second-order electronic transition rate for the anti-Stokes luminescence is calculated using the Fermi golden rule, which includes the influence of this phonon DOS, and is shown to have enhancement effects on the laser cooling efficiency using nanopowders. It is finally concluded that these three enhancement mechanisms are essentially to increase the population of the three participating carriers (electron, photon, and phonon) in the interacting volume, and this also points out directions for enhancing laser cooling performance in bulk materials.

(\mathrm{T}\mathrm{m},\mathrm{Y}\mathrm{b}):{\mathrm{BaY}}_{2}{\mathrm{F}}_{8}

crystals in a wide range of experimentally achievable parameters.