A spatially periodic distribution of excited electronic states is produced in ruby which is placed into the interference region of two light beams derived from a pulsed laser (wavelength 530 nm). The spatially modulated population density acts like an optical grating and is detected by diffraction of a quasi-cw laser beam (488 nm). The lifetimes of the population density gratings are measured for ruby crystals with 0.05 to 5% Cr-doping and compared with the fluorescence lifetimes of the R-lines (694 nm). For the 0.05% ruby both lifetimes are nearly equal. At higher Cr-concentrations the grating decay is considerably faster than the fluorescent decay. The grating lifetimes are independent of the grating period A = 1 to 100 μm. From this observation an upper limit of the diffusion constant for energy transfer between excited electronic states in ruby is estimated.A spatially periodic distribution of excited electronic states is produced in ruby which is placed into the interference region of two light beams derived from a pulsed laser (wavelength 530 nm). The spatially modulated population density acts like an optical grating and is detected by diffraction of a quasi-cw laser beam (488 nm). The lifetimes of the population density gratings are measured for ruby crystals with 0.05 to 5% Cr-doping and compared with the fluorescence lifetimes of the R-lines (694 nm). For the 0.05% ruby both lifetimes are nearly equal. At higher Cr-concentrations the grating decay is considerably faster than the fluorescent decay. The grating lifetimes are independent of the grating period A = 1 to 100 μm. From this observation an upper limit of the diffusion constant for energy transfer between excited electronic states in ruby is estimated.

physica status solidi (a)Apr 16, 197936 citations

Laser enhanced two-photon decay in ruby

Jacques Ducuing, Gerard Hauchecorne, A. Mysyrowicz +1 more

Physics Letters AMar 1, 19698 citations

Influence of impurities on radiation-induced optical processes in ruby

T. S. Bessonova, M. P. Stanislavskii, V. Ya. Khaimov-Mal’kov +1 more

Journal of Applied SpectroscopyMay 1, 19795 citations

Observation of narrow resonances inside homogeneously self-broadened lines in pump-probe reflection experiments

Vladimir A. Sautenkov, R. Gamidov, Antoine Weis

We report the experimental investigation of spectral hole burning and four-wave mixing at the interface of glass and a dense cesium vapor using two tunable diode lasers in a pump-probe experiment. Narrow spectral features were observed in the center of the strongly self-broadened ${\mathrm{D}}_{2}$ line at Cs number density from 9\ifmmode\times\else\texttimes\fi{} ${10}^{15}$ to 2.8\ifmmode\times\else\texttimes\fi{} ${10}^{16}$ ${\mathrm{ncm}}^{\mathrm{\ensuremath{-}}3}$. The origin of the resonances is associated with the coherent scattering of laser beams at a self-induced population grating, and their spectral widths reflect the relaxation rate of the population difference. A simple asymptotic expression is used to fit the spectral line shapes and to infer a population relaxation time of 3.7(2) ns, which is almost an order of magnitude shorter than natural lifetime of the excited state.We report the experimental investigation of spectral hole burning and four-wave mixing at the interface of glass and a dense cesium vapor using two tunable diode lasers in a pump-probe experiment. Narrow spectral features were observed in the center of the strongly self-broadened ${\mathrm{D}}_{2}$ line at Cs number density from 9\ifmmode\times\else\texttimes\fi{}${10}^{15}$ to 2.8\ifmmode\times\else\texttimes\fi{}${10}^{16}$${\mathrm{ncm}}^{\mathrm{\ensuremath{-}}3}$. The origin of the resonances is associated with the coherent scattering of laser beams at a self-induced population grating, and their spectral widths reflect the relaxation rate of the population difference. A simple asymptotic expression is used to fit the spectral line shapes and to infer a population relaxation time of 3.7(2) ns, which is almost an order of magnitude shorter than natural lifetime of the excited state.

Physical Review AApr 1, 199714 citations

High-resolution studies of collision-induced population grating resonances in optical four-wave mixing in sodium vapor

Lewis J. Rothberg, N. Bloembergen

Optical four-wave mixing resonances in sodium vapor induced by collisions with inert buffer gases (He, Ar, Xe, ${\mathrm{N}}_{2}$ ) are characterized at high resolution ( 5 MHz) using lasers tuned near the $D$ lines of Na. These resonances are interpreted in terms of coherent scattering from a population grating established by collisional absorption of the incident radiation. The roles of homogeneous and inhomogeneous contributions to the resonance line shapes are clarified. The line shapes exhibit structure sharper than the predicted linewidth, that characteristic of the $3P$ -to- $3S$ transition rate. We show that this is caused by collision-induced optical pumping which introduces the ground-state lifetime into the grating relaxation physics. These long-lived gratings are exemplified dramatically by experiments in the presence of ${\mathrm{N}}_{2}$ which collisionally quenches the Na $3P$ states. Similar results are obtained in Xe where it is argued that excimer formation with the $3P$ states plays a role in the population dynamics. Model calculations of the effects of sodium level degeneracy on the grating dynamics are presented to support these conclusions. Finally we present data illustrating interference between the collision-induced population grating resonances detailed here and collision-induced coherent Raman resonances between Zeeman sublevels of the ground state.Optical four-wave mixing resonances in sodium vapor induced by collisions with inert buffer gases (He, Ar, Xe, ${\mathrm{N}}_{2}$) are characterized at high resolution ( 5 MHz) using lasers tuned near the $D$ lines of Na. These resonances are interpreted in terms of coherent scattering from a population grating established by collisional absorption of the incident radiation. The roles of homogeneous and inhomogeneous contributions to the resonance line shapes are clarified. The line shapes exhibit structure sharper than the predicted linewidth, that characteristic of the $3P$-to-$3S$ transition rate. We show that this is caused by collision-induced optical pumping which introduces the ground-state lifetime into the grating relaxation physics. These long-lived gratings are exemplified dramatically by experiments in the presence of ${\mathrm{N}}_{2}$ which collisionally quenches the Na $3P$ states. Similar results are obtained in Xe where it is argued that excimer formation with the $3P$ states plays a role in the population dynamics. Model calculations of the effects of sodium level degeneracy on the grating dynamics are presented to support these conclusions. Finally we present data illustrating interference between the collision-induced population grating resonances detailed here and collision-induced coherent Raman resonances between Zeeman sublevels of the ground state.

Physical Review ANov 1, 198436 citations

{\mathrm{D}}_{2}

line at Cs number density from 9\ifmmode\times\else\texttimes\fi{}

{10}^{15}

to 2.8\ifmmode\times\else\texttimes\fi{}

{10}^{16}

${\mathrm{ncm}}^{\mathrm{\ensuremath{-}}3}$. The origin of the resonances is associated with the coherent scattering of laser beams at a self-induced population grating, and their spectral widths reflect the relaxation rate of the population difference. A simple asymptotic expression is used to fit the spectral line shapes and to infer a population relaxation time of 3.7(2) ns, which is almost an order of magnitude shorter than natural lifetime of the excited state.

Optical four-wave mixing resonances in sodium vapor induced by collisions with inert buffer gases (He, Ar, Xe,

{\mathrm{N}}_{2}

) are characterized at high resolution ( 5 MHz) using lasers tuned near the

D

lines of Na. These resonances are interpreted in terms of coherent scattering from a population grating established by collisional absorption of the incident radiation. The roles of homogeneous and inhomogeneous contributions to the resonance line shapes are clarified. The line shapes exhibit structure sharper than the predicted linewidth, that characteristic of the

3P

-to-

3S

transition rate. We show that this is caused by collision-induced optical pumping which introduces the ground-state lifetime into the grating relaxation physics. These long-lived gratings are exemplified dramatically by experiments in the presence of

{\mathrm{N}}_{2}

which collisionally quenches the Na

3P

states. Similar results are obtained in Xe where it is argued that excimer formation with the

3P

states plays a role in the population dynamics. Model calculations of the effects of sodium level degeneracy on the grating dynamics are presented to support these conclusions. Finally we present data illustrating interference between the collision-induced population grating resonances detailed here and collision-induced coherent Raman resonances between Zeeman sublevels of the ground state.