The Journal of Chemical Physics

Absorption and emission spectroscopies of homogeneous and inhomogeneously broadened multilevel systems in strong light fields

Bernhard Dick, Robin M. Hochstrasser

Published Oct 1, 1984• 32 citations

Abstract

A method is introduced to calculate for a model set of molecular levels the spectral line shapes expected for a variety of conventional laser experiments including absorption, hole burning, fluorescence line narrowing, and Raman scattering. The method allows the incident laser field to have arbitrary intensity. Furthermore, the effects of model Gaussian or Lorenzian inhomogeneous distributions are readily incorporated. Earlier results for a two-level system are easily obtained and new results are presented for inhomogeneously broadened two and three level systems, and for the effects of pure dephasing on the strong field spectra. In particular we have described the differences between fluorescence and Raman in strong fields, and the effect of strong fields on the spontaneous emission of inhomogeneously broadened transitions. Some predictions are made regarding line narrowing experiments in the strong-field limit.

DOI: 10.1063/1.448064

Related papers

Line Narrowing Effect in Fully Resonant Four Wave Mixing Spectroscopy in Solids

Hirotoshi Souma

We explain the utility of third-order nonlinear susceptibility, χ (3) (ω 2 ; ±ω 1 , ${\mp}\omega_{1}$, ω 2 ), for the observation of resonances with homogeneous widths from inhomogeneously broadened distributions in three-level systems related to Raman or two-photon allowed electronic transitions. The line narrowing and high resolution capabilities are demonstrated theoretically using a model for inhomogeneous distributions of transitions in which we regard an absorption spectrum as the composition of some inhomogeneously broadened substructures. The experimental methods to separate a signal having frequency ω 2 from ingoing beam at the same frequency are outlined.

Journal of the Physical Society of JapanSep 1, 19832 citations

New Laser Technique for the Identification of Molecular Transitions

N. Skribanowitz, M. J. Kelly, Michael S. Feld

Physical Review ADec 1, 197251 citations

Narrow Resonances with Excitation of Finite Bandwidth Field

Peng Zhou, Mao-Fa Fang, Qing-Ping Zhou +1 more

Jan 1, 19992 citations

Spectra of the scattering of laser radiation in three-level quantum systems

É. G. Pestov

Soviet Journal of Quantum ElectronicsMay 31, 19870 citations

General properties of spectrally inhomogeneous media

С. В. Гапоненко

Cambridge University Press eBooksOct 28, 19980 citations

Nonimpact theory of resonance Raman line shapes in strong radiation fields

Shaul Mukamel, Danielle Grimbert, Yitzhak Rabin

Physical Review AJul 1, 198217 citations

The Journal of Chemical Physics

Absorption and emission spectroscopies of homogeneous and inhomogeneously broadened multilevel systems in strong light fields

Bernhard Dick, Robin M. Hochstrasser

Published Oct 1, 1984• 32 citations

Publisher

Abstract

DOI: 10.1063/1.448064

Related papers

Line Narrowing Effect in Fully Resonant Four Wave Mixing Spectroscopy in Solids

Hirotoshi Souma

We explain the utility of third-order nonlinear susceptibility, χ (3) (ω 2 ; ±ω 1 , ${\mp}\omega_{1}$ , ω 2 ), for the observation of resonances with homogeneous widths from inhomogeneously broadened distributions in three-level systems related to Raman or two-photon allowed electronic transitions. The line narrowing and high resolution capabilities are demonstrated theoretically using a model for inhomogeneous distributions of transitions in which we regard an absorption spectrum as the composition of some inhomogeneously broadened substructures. The experimental methods to separate a signal having frequency ω 2 from ingoing beam at the same frequency are outlined.We explain the utility of third-order nonlinear susceptibility, χ (3) (ω 2 ; ±ω 1 , ${\mp}\omega_{1}$, ω 2 ), for the observation of resonances with homogeneous widths from inhomogeneously broadened distributions in three-level systems related to Raman or two-photon allowed electronic transitions. The line narrowing and high resolution capabilities are demonstrated theoretically using a model for inhomogeneous distributions of transitions in which we regard an absorption spectrum as the composition of some inhomogeneously broadened substructures. The experimental methods to separate a signal having frequency ω 2 from ingoing beam at the same frequency are outlined.

Journal of the Physical Society of JapanSep 1, 19832 citations

New Laser Technique for the Identification of Molecular Transitions

N. Skribanowitz, M. J. Kelly, Michael S. Feld

A laser technique is proposed which may be useful for the assignment of molecular spectra in the visible and infrared regions. The method is based on the resonant interaction of two monochromatic fields with a Doppler-broadened three-level system. Under the appropriate conditions the absorption line shape of one of the transitions shows a complex structure over a narrow section of the Doppler profile, and for sufficiently high laser power the line shape splits into a number of narrow peaks. Analysis of the resulting intensity pattern leads to unambiguous assignment of the angular momentum quantum numbers of the three levels involved. A simple set of rules is given to facilitate interpretation of spectra. The line shapes discussed are also relevant to monochromatic optical pumping of gases and unidirectional laser amplifiers.A laser technique is proposed which may be useful for the assignment of molecular spectra in the visible and infrared regions. The method is based on the resonant interaction of two monochromatic fields with a Doppler-broadened three-level system. Under the appropriate conditions the absorption line shape of one of the transitions shows a complex structure over a narrow section of the Doppler profile, and for sufficiently high laser power the line shape splits into a number of narrow peaks. Analysis of the resulting intensity pattern leads to unambiguous assignment of the angular momentum quantum numbers of the three levels involved. A simple set of rules is given to facilitate interpretation of spectra. The line shapes discussed are also relevant to monochromatic optical pumping of gases and unidirectional laser amplifiers.

Physical Review ADec 1, 197251 citations

Narrow Resonances with Excitation of Finite Bandwidth Field

Peng Zhou, Mao-Fa Fang, Qing-Ping Zhou +1 more

The effect of the laser linewidth on the resonance fluorescence spectrum of a two-level atom is revisited. The novel spectral features, such as hole-burning and dispersive profiles at line centre of the fluorescence spectrum are predicted when the laser linewidth is much greater than its intensity. The unique features result from quantum interference between different dressed-state transition channels. c # 1999 Elsevier Science B.V. PACS : 42.50.Hz; 32.80.-t Keywords: Resonance fluorescence; Laser linewidth; Quantum interference The study of resonance fluorescence spectra has provided much fundamental insight into the subject of atom1light interactions. It is well known that for weak laser field excitation, the spectrum exhibits a Lorentzian lineshape, whereas it develops into the Mollow triplet for strong field excitation [1]. The latter is a direct signature of stimulated emissions and absorptions of the atom during the time interval for one spontaneous decay. Recently, considera...The effect of the laser linewidth on the resonance fluorescence spectrum of a two-level atom is revisited. The novel spectral features, such as hole-burning and dispersive profiles at line centre of the fluorescence spectrum are predicted when the laser linewidth is much greater than its intensity. The unique features result from quantum interference between different dressed-state transition channels. c # 1999 Elsevier Science B.V. PACS : 42.50.Hz; 32.80.-t Keywords: Resonance fluorescence; Laser linewidth; Quantum interference The study of resonance fluorescence spectra has provided much fundamental insight into the subject of atom1light interactions. It is well known that for weak laser field excitation, the spectrum exhibits a Lorentzian lineshape, whereas it develops into the Mollow triplet for strong field excitation [1]. The latter is a direct signature of stimulated emissions and absorptions of the atom during the time interval for one spontaneous decay. Recently, considera...

Jan 1, 19992 citations

Spectra of the scattering of laser radiation in three-level quantum systems

É. G. Pestov

A theoretical investigation is reported of the Raman scattering and fluorescence (doublet) spectra of three-level quantum systems subjected to a strong laser field reducing broadening of the spectral lines caused by adiabatic perturbations (elastic collisions). The dependences of the frequency shifts, widths, and integrated intensities of the spectral components of the doublet on the intensity and frequency of the laser field are derived allowing for the influence of this field on the collision dynamics.A theoretical investigation is reported of the Raman scattering and fluorescence (doublet) spectra of three-level quantum systems subjected to a strong laser field reducing broadening of the spectral lines caused by adiabatic perturbations (elastic collisions). The dependences of the frequency shifts, widths, and integrated intensities of the spectral components of the doublet on the intensity and frequency of the laser field are derived allowing for the influence of this field on the collision dynamics.

Soviet Journal of Quantum ElectronicsMay 31, 19870 citations

General properties of spectrally inhomogeneous media

С. В. Гапоненко

Because of inevitable size distribution, shape variations, different concentration of impurities and defects, and fluctuations of local environment and charge distribution, every ensemble of nanocrystals dispersed in some solid or liquid medium possesses inhomogeneously broadened absorption and emission spectra. Therefore, a number of properties inherent in molecular and atomic inhomogeneously broadened spectra can be a priori foreseen for nanocrystals. These include spectral hole-burning, fluorescence line narrowing under selective excitation, and decay time distribution. At the same time, spectrally selective techniques developed for inhomogeneously broadened molecular and atomic structures have been successfully applied to nanocrystals providing evaluation of individual parameters smeared as a result of inhomogeneous broadening. This chapter gives a brief overview of specific phenomena inherent in all spectrally inhomogeneous media and a survey of the relevant experimental techniques including nonlinear pump-and-probe spectroscopy, fluorescence excitation spectroscopy, and single molecule spectroscopy. Population-induced optical nonlinearity and spectral hole-burning Every real system consisting of particles with discrete energy levels exhibits absorption saturation under intense optical excitation. The only example of a nonsaturable system is an ensemble of ideal harmonic oscillators that possess an infinite number of equally spaced energy levels, optical transitions allowed only for a couple of neighboring levels, and the probability of optical transitions being proportional to the level number (Stepanov and Gribkovskii 1963).Because of inevitable size distribution, shape variations, different concentration of impurities and defects, and fluctuations of local environment and charge distribution, every ensemble of nanocrystals dispersed in some solid or liquid medium possesses inhomogeneously broadened absorption and emission spectra. Therefore, a number of properties inherent in molecular and atomic inhomogeneously broadened spectra can be a priori foreseen for nanocrystals. These include spectral hole-burning, fluorescence line narrowing under selective excitation, and decay time distribution. At the same time, spectrally selective techniques developed for inhomogeneously broadened molecular and atomic structures have been successfully applied to nanocrystals providing evaluation of individual parameters smeared as a result of inhomogeneous broadening. This chapter gives a brief overview of specific phenomena inherent in all spectrally inhomogeneous media and a survey of the relevant experimental techniques including nonlinear pump-and-probe spectroscopy, fluorescence excitation spectroscopy, and single molecule spectroscopy. Population-induced optical nonlinearity and spectral hole-burning Every real system consisting of particles with discrete energy levels exhibits absorption saturation under intense optical excitation. The only example of a nonsaturable system is an ensemble of ideal harmonic oscillators that possess an infinite number of equally spaced energy levels, optical transitions allowed only for a couple of neighboring levels, and the probability of optical transitions being proportional to the level number (Stepanov and Gribkovskii 1963).

Cambridge University Press eBooksOct 28, 19980 citations

Nonimpact theory of resonance Raman line shapes in strong radiation fields

Shaul Mukamel, Danielle Grimbert, Yitzhak Rabin

We develop an expansion for the resonance Raman line shape of a three-level system $|a〉$ , $|b〉$ , and $|c〉$ in an arbitrary strong radiation field, being perturbed by dephasing collisions with foreign gas particles. The microscopic information relevant to the line broadening is expresssed in terms of a hierarchy of $n$ -time correlation functions of the transition dipole operator ( $n=2,4,6,\dots{}$ ). To lowest order ( $n=2$ ) the spectrum is expressed in terms of the three ordinary line-shape functions corresponding to the $\mathrm{ab}$ , $\mathrm{bc}$ , and $\mathrm{ac}$ transitions. The present theory is not restricted to the impact limit and, depending on the collision time scale, may yield very different results from the well-known impact spectra. Explicit calculations of the predicted spectra are presented for a model system.We develop an expansion for the resonance Raman line shape of a three-level system $|a〉$, $|b〉$, and $|c〉$ in an arbitrary strong radiation field, being perturbed by dephasing collisions with foreign gas particles. The microscopic information relevant to the line broadening is expresssed in terms of a hierarchy of $n$-time correlation functions of the transition dipole operator ($n=2,4,6,\dots{}$). To lowest order ($n=2$) the spectrum is expressed in terms of the three ordinary line-shape functions corresponding to the $\mathrm{ab}$, $\mathrm{bc}$, and $\mathrm{ac}$ transitions. The present theory is not restricted to the impact limit and, depending on the collision time scale, may yield very different results from the well-known impact spectra. Explicit calculations of the predicted spectra are presented for a model system.

Physical Review AJul 1, 198217 citations

We explain the utility of third-order nonlinear susceptibility, χ (3) (ω 2 ; ±ω 1 ,

{\mp}\omega_{1}

, ω 2 ), for the observation of resonances with homogeneous widths from inhomogeneously broadened distributions in three-level systems related to Raman or two-photon allowed electronic transitions. The line narrowing and high resolution capabilities are demonstrated theoretically using a model for inhomogeneous distributions of transitions in which we regard an absorption spectrum as the composition of some inhomogeneously broadened substructures. The experimental methods to separate a signal having frequency ω 2 from ingoing beam at the same frequency are outlined.

We develop an expansion for the resonance Raman line shape of a three-level system

|a〉

|b〉

, and

|c〉

in an arbitrary strong radiation field, being perturbed by dephasing collisions with foreign gas particles. The microscopic information relevant to the line broadening is expresssed in terms of a hierarchy of

n

-time correlation functions of the transition dipole operator (

n=2,4,6,\dots{}

). To lowest order (

n=2

) the spectrum is expressed in terms of the three ordinary line-shape functions corresponding to the

\mathrm{ab}

\mathrm{bc}

, and

\mathrm{ac}

transitions. The present theory is not restricted to the impact limit and, depending on the collision time scale, may yield very different results from the well-known impact spectra. Explicit calculations of the predicted spectra are presented for a model system.