IEEE Journal of Quantum Electronics

An experimental upper limit to the nonradiative relaxation time between the4T2and2T1states of ruby

M. Anson, R. C. Smith

Published May 1, 1970• 7 citations

Abstract

An upper limit of 4 ns has been determined for the nonradiative relaxation times between the4T2and2T1states of ruby. This value was deduced from the rate of rise of the red2T1fluorescences from ruby crystals pumped by the second harmonic of a 1.06-μ laser.

DOI: 10.1109/jqe.1970.1076452

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The R-line fluorescence in ruby was excited with the nanosecond light pulses, and the slope of the rise curve was studied as a function of the pulse width at room temperature. The purpose of the experiment was to determine the value or the upper limit of the nonradiative relaxation time between the pump bands 4T1, 2 and the fluorescence state 2E. The upper limit of 5 nsec was determined. A brief review of previous work is given.

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Experimental upper limit to the time of nonradiative relaxation between4 T 2and2 E states in ruby

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IEEE Journal of Quantum Electronics

An experimental upper limit to the nonradiative relaxation time between the4T2and2T1states of ruby

M. Anson, R. C. Smith

Published May 1, 1970• 7 citations

Publisher

Abstract

DOI: 10.1109/jqe.1970.1076452

Related papers

Nonradiative Relaxation Time between 4T1, 2 and 2E States in Ruby

S. A. Pollack

Journal of Applied PhysicsDec 1, 196725 citations

Experimental upper limit to the time of nonradiative relaxation between4 T 2and2 E states in ruby

S. A. Pollack

IEEE Journal of Quantum ElectronicsOct 1, 196814 citations

Experimental studies of non-radiative relaxation rates in solid state laser materials

M. Anson

Techniques for the measurement of non-radiative decay rates between the optically excited states in solid-state laser materials are described. Two crystals have been investigated, ruby (Cr3+:Al2O3) and Sm2+:CaF2. A review of the spectroscopy of these materials is presented with particular emphasis on aspects relevant to non-radiative decay. An experiment is described using a second harmonic Nd3+ Nd:glass Q-switched laser to pump ruby crystals. Limiting non-radiative relaxation times were derived from the rise of fluorescence. Rubies varying in concentration between 0.05% and 0.4% were studied over a range of temperatures, 77 -> 7000 K. 4T2 -> 2E(E + 2A), 4T2 -> 2T1 (Eb) and 4T2 -> 2T1 (2A + Ea) non-radiative relaxations were all found to be <4ns in good agreement with the experimental results of other workers. Two experiments employing a ruby laser to pump Sm2+ :CaF2 are described. The first used a Q-switched laser and, apart from some improvements was similar to the ruby experiment. An upper limit of 4f5 5d pump -> metastable non-radiative decay of 2ns was found for Sm2+:CaF2, The fluorescence decay constant at 295 K was also measured to be 63ns. The second experiment employed a mode-locked laser and the Sm2+:CaF2 non-radiative decay time was <0.5ns. A new effect - provisionally called 'surface emission' - discovered during the ruby measurements, has been examined in detail and the results of this investigation are presented. A phase-shift technique for the measurement of non-radiative decay times is examined in detail. A pilot experiment using a self-mode-locked He-Ne laser at 633 nm to pump Sm2+:CaF2 is described. The non-radiative relaxation time found by this method was <33ps. Suggestions for improved experiments, both pulsed and phase-shifts, are made and the application of the techniques to other materials is discussed.Techniques for the measurement of non-radiative decay rates between the optically excited states in solid-state laser materials are described. Two crystals have been investigated, ruby (Cr3+:Al2O3) and Sm2+:CaF2. A review of the spectroscopy of these materials is presented with particular emphasis on aspects relevant to non-radiative decay. An experiment is described using a second harmonic Nd3+ Nd:glass Q-switched laser to pump ruby crystals. Limiting non-radiative relaxation times were derived from the rise of fluorescence. Rubies varying in concentration between 0.05% and 0.4% were studied over a range of temperatures, 77 -> 7000 K. 4T2 -> 2E(E + 2A), 4T2 -> 2T1 (Eb) and 4T2 -> 2T1 (2A + Ea) non-radiative relaxations were all found to be <4ns in good agreement with the experimental results of other workers. Two experiments employing a ruby laser to pump Sm2+ :CaF2 are described. The first used a Q-switched laser and, apart from some improvements was similar to the ruby experiment. An upper limit of 4f5 5d pump -> metastable non-radiative decay of 2ns was found for Sm2+:CaF2, The fluorescence decay constant at 295 K was also measured to be 63ns. The second experiment employed a mode-locked laser and the Sm2+:CaF2 non-radiative decay time was <0.5ns. A new effect - provisionally called 'surface emission' - discovered during the ruby measurements, has been examined in detail and the results of this investigation are presented. A phase-shift technique for the measurement of non-radiative decay times is examined in detail. A pilot experiment using a self-mode-locked He-Ne laser at 633 nm to pump Sm2+:CaF2 is described. The non-radiative relaxation time found by this method was <33ps. Suggestions for improved experiments, both pulsed and phase-shifts, are made and the application of the techniques to other materials is discussed.

Jan 1, 19710 citations

Picosecond excite-and-probe absorption measurement of the 4T2 state nonradiative lifetime in ruby

Swapan Kumar Gayen, W. -B. Wang, Vladimir Petricevic +2 more

Applied Physics LettersSep 1, 198524 citations

Determination of upper limits for spatial energy diffusion in ruby

P. F. Liao, L. M. Humphrey, D. M. Bloom +1 more

Direct measurements of the diffusion distance of $\overline{E}(^{2}E)$ state excitation by time-resolved degenerate four-wave mixing in ruby are reported. Measurements are made on crystals with ${\mathrm{Cr}}^{3+}$ concentrations varying between 0.05 and 1.55 at.% at 10\ifmmode^\circ\else\textdegree\fi{}K. In all cases an upper limit of 30 nm is determined for the diffusion distance within the fluorescence lifetime.Direct measurements of the diffusion distance of $\overline{E}(^{2}E)$ state excitation by time-resolved degenerate four-wave mixing in ruby are reported. Measurements are made on crystals with ${\mathrm{Cr}}^{3+}$ concentrations varying between 0.05 and 1.55 at.% at 10\ifmmode^\circ\else\textdegree\fi{}K. In all cases an upper limit of 30 nm is determined for the diffusion distance within the fluorescence lifetime.

Physical review. B, Condensed matterNov 15, 197953 citations

Time-resolved spectroscopic study of the excited-state spin-phonon interaction in ruby

John E. Rives, Richard S. Meltzer

The time evolution of the non-spin-flip $2\overline{A}\ensuremath{\leftrightarrow}\overline{E}$ spin-lattice relaxation in ruby has been studied with subnanosecond time resolution, following excitation of the broadband ${\mathrm{Cr}}^{3+}$ states with a ${\mathrm{N}}_{2}$ laser pumped-tunable-dye laser. From the short-time dependence of the ${R}_{1}$ and ${R}_{2}$ emission we directly obtain ${T}_{1}=1.1$ ns for this relaxation. The branching ratio for relaxation from the broadband states to the $\overline{E}$ and $2\overline{A}$ states, respectively, is found to be 2.6. The significance of these measurements in relation to previous estimates of ${T}_{1}$ and to recent 29-${\mathrm{cm}}^{\ensuremath{-}1}$ phonon spectroscopy is discussed.The time evolution of the non-spin-flip $2\overline{A}\ensuremath{\leftrightarrow}\overline{E}$ spin-lattice relaxation in ruby has been studied with subnanosecond time resolution, following excitation of the broadband ${\mathrm{Cr}}^{3+}$ states with a ${\mathrm{N}}_{2}$ laser pumped-tunable-dye laser. From the short-time dependence of the ${R}_{1}$ and ${R}_{2}$ emission we directly obtain ${T}_{1}=1.1$ ns for this relaxation. The branching ratio for relaxation from the broadband states to the $\overline{E}$ and $2\overline{A}$ states, respectively, is found to be 2.6. The significance of these measurements in relation to previous estimates of ${T}_{1}$ and to recent 29-${\mathrm{cm}}^{\ensuremath{-}1}$ phonon spectroscopy is discussed.

Physical review. B, Solid stateSep 1, 197746 citations

Direct measurements of the diffusion distance of

\overline{E}(^{2}E)

state excitation by time-resolved degenerate four-wave mixing in ruby are reported. Measurements are made on crystals with

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

concentrations varying between 0.05 and 1.55 at.% at 10\ifmmode^\circ\else\textdegree\fi{}K. In all cases an upper limit of 30 nm is determined for the diffusion distance within the fluorescence lifetime.

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

states with a

{\mathrm{N}}_{2}

laser pumped-tunable-dye laser. From the short-time dependence of the

{R}_{1}

and

{R}_{2}

emission we directly obtain

{T}_{1}=1.1

ns for this relaxation. The branching ratio for relaxation from the broadband states to the

\overline{E}

and

2\overline{A}

states, respectively, is found to be 2.6. The significance of these measurements in relation to previous estimates of

{T}_{1}

and to recent 29-${\mathrm{cm}}^{\ensuremath{-}1}$ phonon spectroscopy is discussed.