Physical Review A

Optically induced homogeneous line narrowing

A. Szabó, Johann Heber

Published Jun 1, 1984• 19 citations

Abstract

The ${R}_{1}$ dephasing time in ruby (0.05 wt.% ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$) is observed to increase by an order of magnitude when selected transitions of the ${R}_{2}$ line are pumped. Spin flip-flop dephasing in the ground state is suppressed by optically induced depopulation of the $^{4}A_{2}(\ifmmode\pm\else\textpm\fi{}\frac{1}{2})$ levels.

DOI: 10.1103/physreva.29.3452

Related papers

Optically Induced Homogeneous Line Narrowing

A. Szabó, Johann Heber

Journal of the Optical Society of America BJan 1, 19840 citations

Multiple Quantum Transitions and Simultaneous Laser Action of R1 and R2 Lines in Ruby

幹郎片山, 鉄也菅井, 啓三林 +3 more

Dec 8, 19630 citations

Magnetic-field dependence of photon-echo decays in ruby

Joseph Ganem, Y. P. Wang, Richard S. Meltzer +1 more

Physical review. B, Condensed matterApr 1, 199110 citations

Ground-State Spin Memory in the E¯(E2) Level of Ruby in Optical Pumping via the Bands

G. F. Imbusch, Stanley Geschwind

Physical Review LettersAug 1, 196627 citations

Optical hole burning and spectral diffusion in ruby

A. Szabó, Rein K. Kaarli

Physical review. B, Condensed matterDec 1, 199148 citations

Numerical studies of optical dephasing in ruby

Shihua Huang, Alex Szabo

Journal of LuminescenceJul 1, 19966 citations

Physical Review A

Optically induced homogeneous line narrowing

A. Szabó, Johann Heber

Published Jun 1, 1984• 19 citations

Publisher

Abstract

The

{R}_{1}

dephasing time in ruby (0.05 wt.%

{\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}

) is observed to increase by an order of magnitude when selected transitions of the

{R}_{2}

line are pumped. Spin flip-flop dephasing in the ground state is suppressed by optically induced depopulation of the

^{4}A_{2}(\ifmmode\pm\else\textpm\fi{}\frac{1}{2})

levels.

DOI: 10.1103/physreva.29.3452

Related papers

Optically Induced Homogeneous Line Narrowing

A. Szabó, Johann Heber

Recently there has been growing interest in optical dephasing (homogeneous linewidth) mechanisms in solids, both for scientific and technological1 reasons. The role of spin flip-flops (SFF) in producing dephasing has long been recognized in nuclear and electron magnetic resonance, and these studies are now being extended to optical transitions. In particular direct proof of host nuclear SFF optical dephasing of unlike dopant nuclei has been achieved by the observation of magic- angle homogeneous line narrowing.2 This work reports on a new technique for homogeneous line narrowing that demonstrates the existence of electronic SFF optical dephasing by like spins in ruby. The technique relies on selective depopulation of ground- state levels by R2 optical pumping as well as on novel spin thermodynamics in the ground state produced by the strong dipolar coupling between electron spins.Recently there has been growing interest in optical dephasing (homogeneous linewidth) mechanisms in solids, both for scientific and technological1 reasons. The role of spin flip-flops (SFF) in producing dephasing has long been recognized in nuclear and electron magnetic resonance, and these studies are now being extended to optical transitions. In particular direct proof of host nuclear SFF optical dephasing of unlike dopant nuclei has been achieved by the observation of magic- angle homogeneous line narrowing.2 This work reports on a new technique for homogeneous line narrowing that demonstrates the existence of electronic SFF optical dephasing by like spins in ruby. The technique relies on selective depopulation of ground- state levels by R2 optical pumping as well as on novel spin thermodynamics in the ground state produced by the strong dipolar coupling between electron spins.

Journal of the Optical Society of America BJan 1, 19840 citations

Multiple Quantum Transitions and Simultaneous Laser Action of R1 and R2 Lines in Ruby

幹郎片山, 鉄也菅井, 啓三林 +3 more

Dec 8, 19630 citations

Magnetic-field dependence of photon-echo decays in ruby

Joseph Ganem, Y. P. Wang, Richard S. Meltzer +1 more

Measurements of photon-echo decays in dilute ruby ( ${\mathrm{Cr}}_{2}$ ${\mathrm{O}}_{3}$ concentration of 0.018 at. %) in magnetic fields up to 29.5 kG are reported. Echoes from the $^{4}$ ${\mathit{A}}_{2}$ (-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) and $^{4}$ ${\mathit{A}}_{2}$ (-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transitions have dephasing times ( ${\mathit{T}}_{2}$ ) that are directly proportional to the ratio of the magnetic field (B) to the temperature (T), for the range 2.5B/T20 kG/K. A transition in the decay from exponential to nonexponential behavior for B/T>10 kG/K is observed. Decay times for the $^{4}$ ${\mathit{A}}_{2}$ (-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E(-1/2) echo are roughly a factor of 3 longer than for the $^{4}$ ${\mathit{A}}_{2}$ (-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) echo. We attribute the lengthening of ${\mathit{T}}_{2}$ with increasing B/T to the suppression of Cr-Cr spin flip-flops as the population of the upper $^{4}$ ${\mathit{A}}_{2}$ levels decreases.Measurements of photon-echo decays in dilute ruby (${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ concentration of 0.018 at. %) in magnetic fields up to 29.5 kG are reported. Echoes from the $^{4}$${\mathit{A}}_{2}$(-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) and $^{4}$${\mathit{A}}_{2}$(-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transitions have dephasing times (${\mathit{T}}_{2}$) that are directly proportional to the ratio of the magnetic field (B) to the temperature (T), for the range 2.5B/T20 kG/K. A transition in the decay from exponential to nonexponential behavior for B/T>10 kG/K is observed. Decay times for the $^{4}$${\mathit{A}}_{2}$(-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E(-1/2) echo are roughly a factor of 3 longer than for the $^{4}$${\mathit{A}}_{2}$(-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) echo. We attribute the lengthening of ${\mathit{T}}_{2}$ with increasing B/T to the suppression of Cr-Cr spin flip-flops as the population of the upper $^{4}$${\mathit{A}}_{2}$ levels decreases.

Physical review. B, Condensed matterApr 1, 199110 citations

Ground-State Spin Memory in the E¯(E2) Level of Ruby in Optical Pumping via the Bands

G. F. Imbusch, Stanley Geschwind

Physical Review LettersAug 1, 196627 citations

Optical hole burning and spectral diffusion in ruby

A. Szabó, Rein K. Kaarli

Frequency-domain optical hole burning of the ${\mathit{R}}_{1}$ line ${[}^{4}$ ${\mathit{A}}_{2}$ (-1/2)\ensuremath{\leftrightarrows}E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transition] in dilute ruby is studied at 2 K and with a field of 3.6 kG applied along the c axis. A pump-probe (PP) technique is used with precise probe-frequency shifting obtained by an acousto-optic modulator. For sufficiently short PP pulses (50 \ensuremath{\mu}s), two holes (narrow and wide) are observed. The narrow (\ensuremath{\sim}20 kHz half width at half maximum at low power) hole-width dependence on Rabi frequency approximately agrees with that inferred from free-induction-decay measurements. For the present concentration (0.0034 wt. % ${\mathrm{Cr}}_{2}$ ${\mathrm{O}}_{3}$ ) and field, the narrow hole width is determined by fluctuating fields produced by Cr-Cr spin flips [A. Szabo, T. Muramoto, and R. Kaarli, Phys. Rev. B 42, 7769 (1990)]. When the PP delay time is varied, the amplitude of the narrow hole decays with a 1/e time constant of \ensuremath{\sim}300 \ensuremath{\mu}s compared to the E\ifmmode\bar\else\textasciimacron\fi{} fluorescence lifetime of 4 ms. The wide hole (\ensuremath{\sim}500 kHz half width at half maximum) is due to Al-Cr superhyperfine interactions and is created by a spectral diffusion mechanism driven by Al-spin flipping in the host lattice.Frequency-domain optical hole burning of the ${\mathit{R}}_{1}$ line ${[}^{4}$${\mathit{A}}_{2}$(-1/2)\ensuremath{\leftrightarrows}E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transition] in dilute ruby is studied at 2 K and with a field of 3.6 kG applied along the c axis. A pump-probe (PP) technique is used with precise probe-frequency shifting obtained by an acousto-optic modulator. For sufficiently short PP pulses (50 \ensuremath{\mu}s), two holes (narrow and wide) are observed. The narrow (\ensuremath{\sim}20 kHz half width at half maximum at low power) hole-width dependence on Rabi frequency approximately agrees with that inferred from free-induction-decay measurements. For the present concentration (0.0034 wt. % ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$) and field, the narrow hole width is determined by fluctuating fields produced by Cr-Cr spin flips [A. Szabo, T. Muramoto, and R. Kaarli, Phys. Rev. B 42, 7769 (1990)]. When the PP delay time is varied, the amplitude of the narrow hole decays with a 1/e time constant of \ensuremath{\sim}300 \ensuremath{\mu}s compared to the E\ifmmode\bar\else\textasciimacron\fi{} fluorescence lifetime of 4 ms. The wide hole (\ensuremath{\sim}500 kHz half width at half maximum) is due to Al-Cr superhyperfine interactions and is created by a spectral diffusion mechanism driven by Al-spin flipping in the host lattice.

Physical review. B, Condensed matterDec 1, 199148 citations

Numerical studies of optical dephasing in ruby

Shihua Huang, Alex Szabo

Journal of LuminescenceJul 1, 19966 citations

The

{R}_{1}

dephasing time in ruby (0.05 wt.%

{\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}

) is observed to increase by an order of magnitude when selected transitions of the

{R}_{2}

line are pumped. Spin flip-flop dephasing in the ground state is suppressed by optically induced depopulation of the

^{4}A_{2}(\ifmmode\pm\else\textpm\fi{}\frac{1}{2})

levels.

Measurements of photon-echo decays in dilute ruby (

{\mathrm{Cr}}_{2}

{\mathrm{O}}_{3}

concentration of 0.018 at. %) in magnetic fields up to 29.5 kG are reported. Echoes from the

^{4}

{\mathit{A}}_{2}

(-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) and

^{4}

{\mathit{A}}_{2}

(-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transitions have dephasing times (

{\mathit{T}}_{2}

) that are directly proportional to the ratio of the magnetic field (B) to the temperature (T), for the range 2.5B/T20 kG/K. A transition in the decay from exponential to nonexponential behavior for B/T>10 kG/K is observed. Decay times for the

^{4}

{\mathit{A}}_{2}

(-1/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E(-1/2) echo are roughly a factor of 3 longer than for the

^{4}

{\mathit{A}}_{2}

(-3/2)${\mathrm{\ensuremath{\leftrightarrows}}}^{2}$E,E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) echo. We attribute the lengthening of

{\mathit{T}}_{2}

with increasing B/T to the suppression of Cr-Cr spin flip-flops as the population of the upper

^{4}

{\mathit{A}}_{2}

levels decreases.

Frequency-domain optical hole burning of the

{\mathit{R}}_{1}

line

{[}^{4}

{\mathit{A}}_{2}

(-1/2)\ensuremath{\leftrightarrows}E\ifmmode\bar\else\textasciimacron\fi{}(-1/2) transition] in dilute ruby is studied at 2 K and with a field of 3.6 kG applied along the c axis. A pump-probe (PP) technique is used with precise probe-frequency shifting obtained by an acousto-optic modulator. For sufficiently short PP pulses (50 \ensuremath{\mu}s), two holes (narrow and wide) are observed. The narrow (\ensuremath{\sim}20 kHz half width at half maximum at low power) hole-width dependence on Rabi frequency approximately agrees with that inferred from free-induction-decay measurements. For the present concentration (0.0034 wt. %

{\mathrm{Cr}}_{2}

{\mathrm{O}}_{3}

) and field, the narrow hole width is determined by fluctuating fields produced by Cr-Cr spin flips [A. Szabo, T. Muramoto, and R. Kaarli, Phys. Rev. B 42, 7769 (1990)]. When the PP delay time is varied, the amplitude of the narrow hole decays with a 1/e time constant of \ensuremath{\sim}300 \ensuremath{\mu}s compared to the E\ifmmode\bar\else\textasciimacron\fi{} fluorescence lifetime of 4 ms. The wide hole (\ensuremath{\sim}500 kHz half width at half maximum) is due to Al-Cr superhyperfine interactions and is created by a spectral diffusion mechanism driven by Al-spin flipping in the host lattice.