Physical Review A

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

Vladimir A. Sautenkov, R. Gamidov, Antoine Weis

Published Apr 1, 1997• 14 citations

Abstract

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.

DOI: 10.1103/physreva.55.3137

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Coherent Resonances in a Dipole-Broadened Contour of Selective Reflection from the Transparent Insulator–Atomic Rubidium Vapor Interface

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Bulletin of the Lebedev Physics InstituteOct 1, 20237 citations

Origin of spectral holes in pump-probe studies of homogeneously broadened lines

Robert W. Boyd, Shaul Mukamel

Physical Review AApr 1, 1984102 citations

Three-level nonlinear selective reflection at a glass–Cs-vapor interface

Anne Amy‐Klein, Solomon M. Saltiel, O. A. Rabi +1 more

Physical Review AOct 1, 199513 citations

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Physical Review ANov 1, 198436 citations

Excitation dependence of resonance line self-broadening at different atomic densities

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Physical Review A

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

Vladimir A. Sautenkov, R. Gamidov, Antoine Weis

Published Apr 1, 1997• 14 citations

Publisher

Abstract

{\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.

DOI: 10.1103/physreva.55.3137

Related papers

Coherent Resonances in a Dipole-Broadened Contour of Selective Reflection from the Transparent Insulator–Atomic Rubidium Vapor Interface

Vladimir A. Sautenkov, Sergey A. Saakyan, Andrey A. Bobrov +2 more

Abstract Coherent narrow resonances in a homogeneously broadened contour of selective reflection from the interface between a cell window and high-density atomic rubidium vapor, where the dipole broadening greatly exceeds the Doppler width of the unresolved components of rubidium D2 line, are discussed. The formation of coherent resonances is caused by the coherent scattering of probe and pump optical fields from the oscillations of populations of the ground and excited states of atoms at the beat frequency. The width of each resonance depends on the population difference decay rate. Within a simple model conditions are found for observing resonances with a Lorentzian spectral profile. The experimentally recorded coherent resonances are described by a Lorentz function with fitting parameters in the form of amplitude, width, and spectral baseline. In the limit of zero optical saturation the measured half-width of a coherent resonance (HWHM) γres/2π is about 52 MHz, which greatly exceeds the radiative decay rate of the rubidium excited state 5P3/2.Abstract Coherent narrow resonances in a homogeneously broadened contour of selective reflection from the interface between a cell window and high-density atomic rubidium vapor, where the dipole broadening greatly exceeds the Doppler width of the unresolved components of rubidium D2 line, are discussed. The formation of coherent resonances is caused by the coherent scattering of probe and pump optical fields from the oscillations of populations of the ground and excited states of atoms at the beat frequency. The width of each resonance depends on the population difference decay rate. Within a simple model conditions are found for observing resonances with a Lorentzian spectral profile. The experimentally recorded coherent resonances are described by a Lorentz function with fitting parameters in the form of amplitude, width, and spectral baseline. In the limit of zero optical saturation the measured half-width of a coherent resonance (HWHM) γres/2π is about 52 MHz, which greatly exceeds the radiative decay rate of the rubidium excited state 5P3/2.

Bulletin of the Lebedev Physics InstituteOct 1, 20237 citations

Origin of spectral holes in pump-probe studies of homogeneously broadened lines

Robert W. Boyd, Shaul Mukamel

The theory of pump-probe experiments is examined using the nonlinear optical susceptibility ${\ensuremath{\chi}}^{(3)}$. The results of this calculation are shown to differ from those based on a commonly employed heuristic model of pump-probe experiments which assumes that the pump beam "prepares" the system which the probe beam subsequently monitors. This model consequently accounts only for processes where the interactions with the pump field come first in time. The correct expression for the probe absorption line shape as predicted by $\mathrm{Im}{\ensuremath{\chi}}^{(3)}$ contains a sum over all the possible time orderings of the various radiative interactions. The interference terms missing from the simplified treatment are shown to account for the spectral hole in homogeneously broadened lines observed recently [L. W. Hillman et al., Opt. Commun. 45, 416 (1983)]. In addition we derive a generalized expression for ${\ensuremath{\chi}}^{(3)}$ that is valid away from the impact limit and contains a realistic population relaxation ( ${T}_{1}$ ) matrix.The theory of pump-probe experiments is examined using the nonlinear optical susceptibility ${\ensuremath{\chi}}^{(3)}$. The results of this calculation are shown to differ from those based on a commonly employed heuristic model of pump-probe experiments which assumes that the pump beam "prepares" the system which the probe beam subsequently monitors. This model consequently accounts only for processes where the interactions with the pump field come first in time. The correct expression for the probe absorption line shape as predicted by $\mathrm{Im}{\ensuremath{\chi}}^{(3)}$ contains a sum over all the possible time orderings of the various radiative interactions. The interference terms missing from the simplified treatment are shown to account for the spectral hole in homogeneously broadened lines observed recently [L. W. Hillman et al., Opt. Commun. 45, 416 (1983)]. In addition we derive a generalized expression for ${\ensuremath{\chi}}^{(3)}$ that is valid away from the impact limit and contains a realistic population relaxation (${T}_{1}$) matrix.

Physical Review AApr 1, 1984102 citations

Three-level nonlinear selective reflection at a glass–Cs-vapor interface

Anne Amy‐Klein, Solomon M. Saltiel, O. A. Rabi +1 more

We present an experimental study of nonlinear selective reflection at a dielectric--Cs-vapor interface, in a three-level cascade-up scheme. The nonlinear reflection at the Cs ${\mathit{D}}_{2}$ resonance line is monitored in the presence of resonant irradiation at 621 nm or 658 nm (6 ${\mathit{P}}_{3/2}$ \ensuremath{\rightarrow}8 ${\mathit{D}}_{5/2}$ ,9 ${\mathit{S}}_{1/2}$ ). Experimental reflection spectra with either counterpropagating or copropagating light beams are analyzed and compared with the theoretical predictions of F. Schuller et al. [Phys. Rev. A 47, 519 (1993)]. For a blue-detuned pump and copropagating geometry an alternative type of three-level coherent reflection resonances, specifically associated with desorbing atoms, is observed. Also observed is the nonlinear reflection associated with the off-resonant, two-photon dispersion of atoms moving parallel to the window surface. Probe beam saturation is responsible for the appearance of additional resonant features in reflection spectra. Finally we analyze crossover spectral resonances which arise from nondegenerate, four-wave-mixing processes induced by the combined influence of counterpropagating pump and probe beams, and the pump beam being partially reflected by the window.We present an experimental study of nonlinear selective reflection at a dielectric--Cs-vapor interface, in a three-level cascade-up scheme. The nonlinear reflection at the Cs ${\mathit{D}}_{2}$ resonance line is monitored in the presence of resonant irradiation at 621 nm or 658 nm (6${\mathit{P}}_{3/2}$\ensuremath{\rightarrow}8${\mathit{D}}_{5/2}$,9${\mathit{S}}_{1/2}$). Experimental reflection spectra with either counterpropagating or copropagating light beams are analyzed and compared with the theoretical predictions of F. Schuller et al. [Phys. Rev. A 47, 519 (1993)]. For a blue-detuned pump and copropagating geometry an alternative type of three-level coherent reflection resonances, specifically associated with desorbing atoms, is observed. Also observed is the nonlinear reflection associated with the off-resonant, two-photon dispersion of atoms moving parallel to the window surface. Probe beam saturation is responsible for the appearance of additional resonant features in reflection spectra. Finally we analyze crossover spectral resonances which arise from nondegenerate, four-wave-mixing processes induced by the combined influence of counterpropagating pump and probe beams, and the pump beam being partially reflected by the window.

Physical Review AOct 1, 199513 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

Excitation dependence of resonance line self-broadening at different atomic densities

Hebin Li, Vladimir A. Sautenkov, Yuri V. Rostovtsev +1 more

We study the dipole–dipole spectral broadening of a resonance line at high atomic densities when the self-broadening dominates. The selective reflection spectrum of a weak probe beam from the interface of the cell window and rubidium vapour is recorded in the presence of a far-detuned pump beam. The excitation due to the pump reduces the self-broadening. We found that the self-broadening reduction dependence on the pump power is atomic density independent. These results provide experimental evidence for the disordered exciton based theory of self-broadening, and can be useful for the description of the interaction of a strong optical field with a dense resonance medium.We study the dipole–dipole spectral broadening of a resonance line at high atomic densities when the self-broadening dominates. The selective reflection spectrum of a weak probe beam from the interface of the cell window and rubidium vapour is recorded in the presence of a far-detuned pump beam. The excitation due to the pump reduces the self-broadening. We found that the self-broadening reduction dependence on the pump power is atomic density independent. These results provide experimental evidence for the disordered exciton based theory of self-broadening, and can be useful for the description of the interaction of a strong optical field with a dense resonance medium.

arXiv:0811.0575Journal of Physics B Atomic Molecular and Optical PhysicsMar 9, 200939 citations

Coherent Population Trapping resonances on lower atomic levels of Doppler broadened optical lines

Ersoy Şahin, G. Özen, Ramiz Hamid +2 more

We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of the weak probe light beam by the counterpropagating two-frequency pumping radiation. Our experimental investigations have been carried out on example of nonclosed three level Lambda systems formed by spectral components of the Doppler broadened D2 line of cesium atoms. We have established that CPT resonances in transmission of the probe beam (in the cesium vapor), at definite conditions, may have not only more contrast but also much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pumping radiation. Thus CPT resonances, detected by the elaborated method, may be used in atomic frequency standards and sensitive magnetometers (based on the CPT phenomenon) and also in ultahigh resolution spectroscopy of atoms and molecules.We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of the weak probe light beam by the counterpropagating two-frequency pumping radiation. Our experimental investigations have been carried out on example of nonclosed three level Lambda systems formed by spectral components of the Doppler broadened D2 line of cesium atoms. We have established that CPT resonances in transmission of the probe beam (in the cesium vapor), at definite conditions, may have not only more contrast but also much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pumping radiation. Thus CPT resonances, detected by the elaborated method, may be used in atomic frequency standards and sensitive magnetometers (based on the CPT phenomenon) and also in ultahigh resolution spectroscopy of atoms and molecules.

arXiv:1212.3834Dec 16, 20121 citation

{\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}

{T}_{1}

) matrix.

We present an experimental study of nonlinear selective reflection at a dielectric--Cs-vapor interface, in a three-level cascade-up scheme. The nonlinear reflection at the Cs

{\mathit{D}}_{2}

resonance line is monitored in the presence of resonant irradiation at 621 nm or 658 nm (6

{\mathit{P}}_{3/2}

\ensuremath{\rightarrow}8

{\mathit{D}}_{5/2}

{\mathit{S}}_{1/2}

). Experimental reflection spectra with either counterpropagating or copropagating light beams are analyzed and compared with the theoretical predictions of F. Schuller et al. [Phys. Rev. A 47, 519 (1993)]. For a blue-detuned pump and copropagating geometry an alternative type of three-level coherent reflection resonances, specifically associated with desorbing atoms, is observed. Also observed is the nonlinear reflection associated with the off-resonant, two-photon dispersion of atoms moving parallel to the window surface. Probe beam saturation is responsible for the appearance of additional resonant features in reflection spectra. Finally we analyze crossover spectral resonances which arise from nondegenerate, four-wave-mixing processes induced by the combined influence of counterpropagating pump and probe beams, and the pump beam being partially reflected by the window.

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.