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

Luminescent instabilities and nonradiative processes in rare earth systems.

Shawn M. Redmond

Published Jan 1, 2003• 3 citations
OpenAlex

Abstract

This research is an outgrowth of earlier experiments that demonstrated bistable luminescence in heavy metal halide crystals doped with trivalent ytterbium ions. This type of instability has importance as a fundamentally new physical phenomenon with a potential application for fast all-optical switching as well as a limitation on compact solid state laser performance. In this thesis, the investigation of luminescent instabilities is extended to bistable energy transfer processes in crystals and to the observation of bistable blackbody emission in rare earth nanopowders. High resolution laser spectroscopy was used to study bistable luminescence and energy transfer in Yb,Er:CsCdBr3 crystals at cryogenic temperatures. For the first time, it was found that bistable behavior associated with Yb 3+ ions was transferred to Er 3+ through resonant energy transfer. Bistability of the resulting sensitized luminescence caused sufficiently dramatic changes in the crystal dynamics so as to change the color of emission from yellow to green. This color changing phenomenon is fully explained in the present work and is referred to as chromatic switching. Temperature is a critical variable that is known to govern luminescent instabilities in all current theories. Therefore, in a search for new systems with luminescent instabilities at high temperatures, materials with extreme thermal properties were investigated as part of this research. Yb,Er:Y 2O3 nanopowders were selected for this purpose. Nanopowders exhibit greatly reduced thermal conductivity and were verified during the course of this work to cause enhanced absorption as the result of multiple scattering. Significant spectral differences between Yb,Er:Y2O 3 nanopowders and single crystals also emerged. Measurements of erbium upconversion luminescence versus pump intensity in resonance with the ytterbium absorption transition revealed striking new optical phenomena: strong luminescent quenching, intense bistable blackbody emission, and the formation of single crystal micro-tubes directly from powder samples. A simple theoretical model was successfully developed to explain all these optical effects by a detailed balance approach to thermal transport that explicitly included erbium and ytterbium atomic level occupation probabilities, blackbody radiation and radiation trapping. Calculations of nanopowder sample luminescence accurately reproduced experimentally observed quenching, the onset of blackbody emission, bistability and details of hysteresis loops. The model also predicted that absorbed powers of less than 15 mW could melt yttria nanopowders (melting point = 2410°C), again in agreement with experiments. This work is expected to enable new approaches to laser processing of ceramics and laser machining of reflective metals, notably aluminum, using low power lasers.

Related papers

Luminescent instabilities in dense rare earth ion systems.

Amos Kuditcher

This thesis reports experiments and theory on intrinsic mirrorless bistability in the luminescence of ytterbium-doped crystals and glasses. The main results are the observation of intrinsically bistable luminescence at room temperature and chromatic switching at low temperature, reported here for the first time. The nonlinear dynamics responsible for these optical phenomena are shown to arise from ion-ion interactions controlled by the application of resonant electromagnetic fields. On the theoretical side, the classical Lorentz local field correction is shown to be the lowest order term of radiation-driven correlation contributions to local polarization which arise from inter-ion coherences and cooperative relaxation and frequency shifts beyond the dynamic shift are predicted. The nonlinear Maxwell-Bloch equations are extended to describe energy transfer between different species of ions predicting bistability in excited state populations which then emit bistable luminescence as a consequence, and an intensity dependent transfer rate is predicted. Diffusive excitation migration in space is also explored as a possible mechanism for generating multiple instabilities, but is not predicted to give rise to hysteresis loops by itself. On the experimental side, original observations of intrinsic optical switching and hysteresis are reported in the luminescence of Yb:CsCdBr 3 and Yb, Tm:glass. Evidence of cross-coupling between different impurities is also presented, together with spectroscopic details of intrinsic chromatic switching between different luminescent transitions of the acceptor species in Yb, Er:CsCdBr3 excited at the infrared Yb resonance wavelength. Conclusive spectroscopic evidence that excludes thermal effects as responsible for low temperature intrinsic switching is also presented. Room temperature intrinsic optical switching and hysteresis are reported for the first time in bulk Yb,Tm:glass samples. Switching, hysteresis, and clamping of laser output from waveguide channels fabricated in the glass material are also reported and indicate fundamental design limitations for compact optical amplifiers and oscillators.

•Jan 1, 1999•0 citations

Intrinsic bistability effect of Yb-sensitized Tm upconversion emission in zirconium dioxide nanocrystal

D. X. Wang, M. Nie, Zhiguo Zhang +5 more

Intrinsic bistability in active optical compounds doped with rare-earth ions has attracted widespread interest because of its relevance for optical signal switching and routing. In this paper, room temperature strong bistability effect of Ybsensitized Tm upconversion emission is reported in zirconium dioxide nanocrystal host matrix under infrared diode laser irradiation. The distinct optical bistability behavior is simultaneously observed in three emission bands of Tm ion around 480, 650/680 and 800 nm which are assigned to the radiative transitions of 1G4→3H6, 1G4→3F4/3F2,3→3H6, and 3H4→3H6, respectively. The bistability loops exhibit uniformly clockwise cycle characterized by a relatively lower trace of emission intensity at decreasing pump power than the trace at increasing pump power. Multiphoton upconversion processes are analyzed to determine the Yb→Tm energy transfer mechanism. Such strong bistability effect is associated with thermally enhanced nonradiative decay and reduced luminescence quantum yield due to the strong pump-induced local thermal loading.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 19, 2011•4 citations

Intrinsic chromatic switching of visible luminescence in Yb^3+,Er^3+:CsCdBr_3

Shawn M. Redmond, Stephen Colby Rand

Bistability is reported in sensitized Er3+ luminescence driven by an Yb3+ transition that previously revealed an Yb3+ luminescent instability. To our knowledge this is the first report of bistable energy transfer between different rare-earth ions.

Optics Letters•Feb 1, 2003•29 citations

Bistable chromatic switching in 648 nm laser pumped Tm-doped crystal

Li Li, Xinlu Zhang, Lixue Chen

Intrinsic optical bistability is of great interest and has potential applications in all-optical communication. In the present work, we have extended occurrences of bistable chromatic switching to a new rare-earth-doped system, namely single Tm-doped laser crystal pumped at 648 nm avalanche wavelength. Intrinsic bistability and chromatic switching of fluorescence emission are theoretically predicted, based on the rate equation theory. By using a four-order Runge-Kutta technique, chromatic switching spectra and bistable hysteresis loop are studied numerically in detail. The numerical results show that intrinsic chromatic switching of visible-infrared spectra is achievable experimentally corresponding to the transitions of Tm 1D2→3H6 (357 nm), 1G4→3H6 (469 nm), 3H4→3H6 (787 nm), 3F4→3H6 (1716 nm), as pump power increases far beyond avalanche threshold from low power level. Furthermore, we have found that the chromatic switching appears bistable in the emission spectra for pump intensity in the vicinity of avalanche threshold. The bistable hysteresis loops of luminescence are also demonstrated numerically for the dominant emission band. Intrinsic bistable chromatic switching in Tm-doped crystal is mediated by resonant excited-state absorption up-conversion.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 29, 2007•1 citation

Investigation of Non-linear Energy Transfer Dynamics of Erbium in Yttrium Aluminum Garnet

Christian Vega

Yttrium Aluminum Garnet (YAG, Y_3 〖Al〗_5 O_12) crystals doped with Erbium have posed an interesting position in the field of rare earth solid state lasers as they possess the property of self-saturation, in which the upper energy level in a laser has a much shorter lifetime than that of the lower level. This is the case of the 2.94μm transition in Er:YAG. That property at first seems to make this material unfit for use as a laser gain medium, however further research into these classes of rare earth materials revealed interesting non-liner energy transfer mechanisms that allow it to be a useful mid wave infra-red (MWIR) coherent source in the continuous wave (CW) and pulsed regimes. This came to fruition due to decades of modeling and spectroscopic research investigating the non-linear energy transfer mechanisms of excited state absorption (ESA), energy transfer up-conversion (ETU), and cross relaxation (XR). These effects show up in the rise and fall times of the levels observed through fluorescence. Resulting in the non-exponential rise and fall characteristics and having a squared or even cubed relation to the population. The population evolution for each of the lasing levels is now affected by ions recycling energy and in turn cause the lifetimes of the levels to “effectively” change to a point where simple linear models do not adequately describe the system and its performance. The non-linear energy transfer dynamics of Er:YAG are modeled under high resonant pump conditions. By pumping with selective resonant pumps, the interaction dynamics of the (_ ^4)I_(11/2) and the (_ ^4)I_(13/2) levels in the Erbium ion reveal the contributions from generally ignored non-linear energy transfer mechanisms. Specifically, the multi-photon effect known as excited state absorption (ESA) is modeled by measuring and characterizing the cross section in single crystal Er:YAG samples utilizing a pump and probe technique coupled with transient fluorescence measurements. The measured ESA cross section is then included in the rate equation modeling.

•Jan 1, 2018•0 citations

Enhanced nonradiative relaxation and photoluminescence quenching in random, doped nanocrystalline powders

Xiulin Ruan, Massoud Kaviany

Nonradiative relaxation and photoluminescence quenching in nanocrystalline powders doped with rare-earth elements are of interest in optical bistability, random laser, and other optoelectronic applications. Here, the luminescence quenching of a one-dimensional random medium made of multilayer nanoparticles (Y2O3) doped with rare-earth elements (Yb3+) is analyzed by considering the transport, transition, and interaction of the fundamental energy carriers. The nonradiative decay and luminescence quenching in random media are enhanced compared to single crystals, due to multiple scattering, enhanced absorption, and low thermal conductivity. The coherent wave treatment is used to calculate the photon absorption, allowing for field enhancement and photon localization. The luminescent and thermal emission is considered as incoherent. The size-dependent absorption coefficient and penetration depth are observed. The nonradiative decay is identified as a multiphonon relaxation process, and is found to be enhanced compared to bulk materials. The luminescence quenching and nonlinear thermal emission, occurring with increasing irradiation intensity, are predicted.

Journal of Applied Physics•May 11, 2005•27 citations
This research is an outgrowth of earlier experiments that demonstrated bistable luminescence in heavy metal halide crystals doped with trivalent ytterbium ions. This type of instability has importance as a fundamentally new physical phenomenon with a potential application for fast all-optical switching as well as a limitation on compact solid state laser performance. In this thesis, the investigation of luminescent instabilities is extended to bistable energy transfer processes in crystals and to the observation of bistable blackbody emission in rare earth nanopowders. High resolution laser spectroscopy was used to study bistable luminescence and energy transfer in Yb,Er:CsCdBr3 crystals at cryogenic temperatures. For the first time, it was found that bistable behavior associated with Yb 3+ ions was transferred to Er 3+ through resonant energy transfer. Bistability of the resulting sensitized luminescence caused sufficiently dramatic changes in the crystal dynamics so as to change the color of emission from yellow to green. This color changing phenomenon is fully explained in the present work and is referred to as chromatic switching. Temperature is a critical variable that is known to govern luminescent instabilities in all current theories. Therefore, in a search for new systems with luminescent instabilities at high temperatures, materials with extreme thermal properties were investigated as part of this research. Yb,Er:Y 2O3 nanopowders were selected for this purpose. Nanopowders exhibit greatly reduced thermal conductivity and were verified during the course of this work to cause enhanced absorption as the result of multiple scattering. Significant spectral differences between Yb,Er:Y2O 3 nanopowders and single crystals also emerged. Measurements of erbium upconversion luminescence versus pump intensity in resonance with the ytterbium absorption transition revealed striking new optical phenomena: strong luminescent quenching, intense bistable blackbody emission, and the formation of single crystal micro-tubes directly from powder samples. A simple theoretical model was successfully developed to explain all these optical effects by a detailed balance approach to thermal transport that explicitly included erbium and ytterbium atomic level occupation probabilities, blackbody radiation and radiation trapping. Calculations of nanopowder sample luminescence accurately reproduced experimentally observed quenching, the onset of blackbody emission, bistability and details of hysteresis loops. The model also predicted that absorbed powers of less than 15 mW could melt yttria nanopowders (melting point = 2410°C), again in agreement with experiments. This work is expected to enable new approaches to laser processing of ceramics and laser machining of reflective metals, notably aluminum, using low power lasers.
This thesis reports experiments and theory on intrinsic mirrorless bistability in the luminescence of ytterbium-doped crystals and glasses. The main results are the observation of intrinsically bistable luminescence at room temperature and chromatic switching at low temperature, reported here for the first time. The nonlinear dynamics responsible for these optical phenomena are shown to arise from ion-ion interactions controlled by the application of resonant electromagnetic fields. On the theoretical side, the classical Lorentz local field correction is shown to be the lowest order term of radiation-driven correlation contributions to local polarization which arise from inter-ion coherences and cooperative relaxation and frequency shifts beyond the dynamic shift are predicted. The nonlinear Maxwell-Bloch equations are extended to describe energy transfer between different species of ions predicting bistability in excited state populations which then emit bistable luminescence as a consequence, and an intensity dependent transfer rate is predicted. Diffusive excitation migration in space is also explored as a possible mechanism for generating multiple instabilities, but is not predicted to give rise to hysteresis loops by itself. On the experimental side, original observations of intrinsic optical switching and hysteresis are reported in the luminescence of Yb:CsCdBr 3 and Yb, Tm:glass. Evidence of cross-coupling between different impurities is also presented, together with spectroscopic details of intrinsic chromatic switching between different luminescent transitions of the acceptor species in Yb, Er:CsCdBr3 excited at the infrared Yb resonance wavelength. Conclusive spectroscopic evidence that excludes thermal effects as responsible for low temperature intrinsic switching is also presented. Room temperature intrinsic optical switching and hysteresis are reported for the first time in bulk Yb,Tm:glass samples. Switching, hysteresis, and clamping of laser output from waveguide channels fabricated in the glass material are also reported and indicate fundamental design limitations for compact optical amplifiers and oscillators.
Intrinsic bistability in active optical compounds doped with rare-earth ions has attracted widespread interest because of its relevance for optical signal switching and routing. In this paper, room temperature strong bistability effect of Ybsensitized Tm upconversion emission is reported in zirconium dioxide nanocrystal host matrix under infrared diode laser irradiation. The distinct optical bistability behavior is simultaneously observed in three emission bands of Tm ion around 480, 650/680 and 800 nm which are assigned to the radiative transitions of 1G4→3H6, 1G4→3F4/3F2,3→3H6, and 3H4→3H6, respectively. The bistability loops exhibit uniformly clockwise cycle characterized by a relatively lower trace of emission intensity at decreasing pump power than the trace at increasing pump power. Multiphoton upconversion processes are analyzed to determine the Yb→Tm energy transfer mechanism. Such strong bistability effect is associated with thermally enhanced nonradiative decay and reduced luminescence quantum yield due to the strong pump-induced local thermal loading.
Intrinsic optical bistability is of great interest and has potential applications in all-optical communication. In the present work, we have extended occurrences of bistable chromatic switching to a new rare-earth-doped system, namely single Tm-doped laser crystal pumped at 648 nm avalanche wavelength. Intrinsic bistability and chromatic switching of fluorescence emission are theoretically predicted, based on the rate equation theory. By using a four-order Runge-Kutta technique, chromatic switching spectra and bistable hysteresis loop are studied numerically in detail. The numerical results show that intrinsic chromatic switching of visible-infrared spectra is achievable experimentally corresponding to the transitions of Tm 1D2→3H6 (357 nm), 1G4→3H6 (469 nm), 3H4→3H6 (787 nm), 3F4→3H6 (1716 nm), as pump power increases far beyond avalanche threshold from low power level. Furthermore, we have found that the chromatic switching appears bistable in the emission spectra for pump intensity in the vicinity of avalanche threshold. The bistable hysteresis loops of luminescence are also demonstrated numerically for the dominant emission band. Intrinsic bistable chromatic switching in Tm-doped crystal is mediated by resonant excited-state absorption up-conversion.
Yttrium Aluminum Garnet (YAG, Y_3 〖Al〗_5 O_12) crystals doped with Erbium have posed an interesting position in the field of rare earth solid state lasers as they possess the property of self-saturation, in which the upper energy level in a laser has a much shorter lifetime than that of the lower level. This is the case of the 2.94μm transition in Er:YAG. That property at first seems to make this material unfit for use as a laser gain medium, however further research into these classes of rare earth materials revealed interesting non-liner energy transfer mechanisms that allow it to be a useful mid wave infra-red (MWIR) coherent source in the continuous wave (CW) and pulsed regimes. This came to fruition due to decades of modeling and spectroscopic research investigating the non-linear energy transfer mechanisms of excited state absorption (ESA), energy transfer up-conversion (ETU), and cross relaxation (XR). These effects show up in the rise and fall times of the levels observed through fluorescence. Resulting in the non-exponential rise and fall characteristics and having a squared or even cubed relation to the population. The population evolution for each of the lasing levels is now affected by ions recycling energy and in turn cause the lifetimes of the levels to “effectively” change to a point where simple linear models do not adequately describe the system and its performance. The non-linear energy transfer dynamics of Er:YAG are modeled under high resonant pump conditions. By pumping with selective resonant pumps, the interaction dynamics of the (_ ^4)I_(11/2) and the (_ ^4)I_(13/2) levels in the Erbium ion reveal the contributions from generally ignored non-linear energy transfer mechanisms. Specifically, the multi-photon effect known as excited state absorption (ESA) is modeled by measuring and characterizing the cross section in single crystal Er:YAG samples utilizing a pump and probe technique coupled with transient fluorescence measurements. The measured ESA cross section is then included in the rate equation modeling.
Nonradiative relaxation and photoluminescence quenching in nanocrystalline powders doped with rare-earth elements are of interest in optical bistability, random laser, and other optoelectronic applications. Here, the luminescence quenching of a one-dimensional random medium made of multilayer nanoparticles (Y2O3) doped with rare-earth elements (Yb3+) is analyzed by considering the transport, transition, and interaction of the fundamental energy carriers. The nonradiative decay and luminescence quenching in random media are enhanced compared to single crystals, due to multiple scattering, enhanced absorption, and low thermal conductivity. The coherent wave treatment is used to calculate the photon absorption, allowing for field enhancement and photon localization. The luminescent and thermal emission is considered as incoherent. The size-dependent absorption coefficient and penetration depth are observed. The nonradiative decay is identified as a multiphonon relaxation process, and is found to be enhanced compared to bulk materials. The luminescence quenching and nonlinear thermal emission, occurring with increasing irradiation intensity, are predicted.