The author has considered the interference spectra arising from the competition between short- and long-lifetime excitations, which have been induced in the ground state of a three-level atom by a strong and a weak laser field, respectively. The atom is supposed to have a strong and a weak transition leading to an electric-dipole-allowed excited state and to a metastable excited state, respectively. Expressions have been derived for the spectral functions describing the induced spectra in the ground state of the atom in the low- and high-intensity limits of a strong laser field. The competition between the short- and the long-lifetime excitations results in the decrease of the intensity of the short-lifetime excitation near the centre of the peak by an amount equal to 50% of its original value. The computed spectra have been presented graphically and discussed. It is shown that the decrease of the intensity of the short-lifetime excitation may provide a measure of the width of the long-lifetime excitation.
The author has considered the interference spectra arising from the competition between short- and long-lifetime excitations, which have been induced in the ground state of a three-level atom by a strong and a weak laser field, respectively. The atom is supposed to have a strong and a weak transition leading to an electric-dipole-allowed excited state and to a metastable excited state, respectively. Expressions have been derived for the spectral functions describing the induced spectra in the ground state of the atom in the low- and high-intensity limits of a strong laser field. The competition between the short- and the long-lifetime excitations results in the decrease of the intensity of the short-lifetime excitation near the centre of the peak by an amount equal to 50% of its original value. The computed spectra have been presented graphically and discussed. It is shown that the decrease of the intensity of the short-lifetime excitation may provide a measure of the width of the long-lifetime excitation.
Numerical calculations are presented for the interference spectra of a laser-excited three-level atom, where the strong and the weak atomic transitions are driven by resonant and nonresonant laser fields, respectively. The spectral functions describing the interference spectra for the electric dipole allowed excited state have been considered in the low- and high-intensity limit of the laser field operating in the strong transition. The interference spectra arise from the competition between short-lifetime spontaneous processes and short- and long-lifetime excitations induced by the strong and the weak laser fields, respectively. Both laser fields have been treated as quantized and as classical entities. The computed spectra have been presented graphically for different values of the Rabi frequencies and detunings of the weak laser field. It is shown that the decrease in the intensity of the short-lifetime excitation may provide a measure of the spectral width of the long-lifetime excitation.
We considered the excitation spectra for the excited states of a three-level atom, where the strong and the weak atomic transitions are driven by resonant and nonresonant laser fields, respectively. The spectral functions describing the excitation spectra for the electric dipole allowed excited state and for the metastable state of the atom have been derived when both laser fields are quantized as well as when they are treated as classical entities. In the low-intensity limit of the laser field operating in the strong transition, there are two short-lifetime excitations, the spontaneous one and the induced one, which appear at the same frequency, and a long-lifetime excitation induced by the weak laser field. These excitations compete with each other at resonance as well as at finite detunings of the weak laser field. In the high-intensity limit of the laser field operating in the strong transition, the competition is between the short- and the long-lifetime side bands, which are induced by the strong and the weak laser fields, respectively. The ratio of the maximum intensities of the peaks describing the long- and the short-lifetime excitations exhibits a resonance variation with the detuning of the weak laser field. Comparison between the results obtained when the laser fields are treated as quantized and as classical entities is made.
We have considered the interference spectra arising from the competition between a spontaneous process and one induced by a laser field in a two-level atom. Expressions for the spectral functions have been derived describing the spectra of the excited and ground states of the atom in the low- and high-intensity limit of the laser field. For the excited-state spectra in the low-intensity limit, the frequency profiles of the two peaks, which arise from the spontaneous and the induced processes, cancel each other out completely near the center of the line, while for the ground state the induced process dominates. For finite values of the detuning, the spectra of the excited state consist of two peaks, which have positive and negative frequency profiles, respectively. The computed spectra have been graphically presented and discussed. In the high-intensity limit, the dynamic Stark effect dominates the spectra of the excited and ground states of the atom. Expressions for the correlation functions have been derived that describe the emission or the absorption of a laser photon at two different times. The derived expressions for the corresponding delay functions in the low- and high-intensity limits have been found to be identical to those recently proposed in the literature. The laser field has been treated as a classical as well as a quantized entity.
The author has considered the interference spectra arising from the competition between absorption and stimulated emission processes, which have been induced by two laser fields operating at a two-photon resonance with a three-level atom in the ' Lambda ' configuration. In the low intensity limit of both laser fields, the induced spectrum in the ground state consists mainly of a peak, whose height and asymmetry depend strongly on the value of the detuning of the laser fields. In the absence of detuning, the height of the induced peak takes positive values implying that the physical process of absorption (attenuation) takes place, while at finite detunings the height of the peak becomes negative indicating the frequencies at which stimulated emission (amplification) is likely to occur. The spectra arising from the emission of a laser photon by the excited state consist of two peaks describing stimulated emission and induced absorption, respectively, where the former dominates the latter for small values of the Rabi frequencies but for higher ones, cancel each other out.
The interference spectra arising from the competition between a spontaneous process and an induced one by two laser fields, which interact on two-photon resonance with a three-level atom in the Lambda configuration have been considered. In the low intensity limit of both laser fields, the frequency profiles of the two peaks, which arise from the spontaneous and induced processes, respectively, cancel each other out completely at the centre of the line for zero detuning and at the finite values of the detuning as well. At those frequencies, the fluorescent light totally disappears. The interference spectra arising from the absorption of a laser photon by the ground state of the atom consists of two peaks describing the induced processes of absorption and stimulated emission, respectively.
We consider the interference spectra arising from the competition between a spontaneous process and two processes induced by two laser fields, which are coupled with a three-level atom in the "Λ" configuration. In the low-intensity limit of both laser fields and on two-photon resonance, the frequency profiles of the two peaks, which arise from the spontaneous and induced processes, cancel each other out completely at the center of the line for zero detuning and at the finite values of the detuning as well. At high intensities of the laser fields and on two-photon resonance, the dynamic Stark effect dominates the spectra of the excited state of the atom. Expressions for the interference spectra and correlation functions are derived, which describe the physical process of the absorption of a laser photon at two different times by the ground state of the atom. Interference spectra and correlation functions are calculated for the two-photon off-resonance and for the proces of the absorption of a photon by the ground state of the atom. In this case, the intensities of the frequency dips take negative values indicating that stimulated emission prevails for certain values of the detunings. Using values for the parameters involved close to those for Ba+, the computed two-photon resonance and off-resonance spectra are graphically presented and discussed.