We study the interplay between resonant multiphoton population transfer and strong field ionization in potassium atoms, by calculating their response to intense, midinfrared (MIR) radiation. We use wavelengths close to the three or five photon resonance between the ground $4s$ state and the first excited $4p$ state, and find that the amount of population transferred to the excited state as a function of wavelength and intensity shows clear signatures of these resonances. The ionization yield also shows moderate resonant enhancement for intermediate intensities. We can further distinguish between population transfer to and ionization of the $4p$ state by using a chirped laser pulse to temporally separate the two processes. We find that the amount of population remaining in the $4p$ state at the end of the pulse shows a pronounced sensitivity to the sign of the chirp whereas the total amount of ionization does not. From this we conclude that direct, nonresonant ionization of the ground state competes strongly with the resonant process.We study the interplay between resonant multiphoton population transfer and strong field ionization in potassium atoms, by calculating their response to intense, midinfrared (MIR) radiation. We use wavelengths close to the three or five photon resonance between the ground $4s$ state and the first excited $4p$ state, and find that the amount of population transferred to the excited state as a function of wavelength and intensity shows clear signatures of these resonances. The ionization yield also shows moderate resonant enhancement for intermediate intensities. We can further distinguish between population transfer to and ionization of the $4p$ state by using a chirped laser pulse to temporally separate the two processes. We find that the amount of population remaining in the $4p$ state at the end of the pulse shows a pronounced sensitivity to the sign of the chirp whereas the total amount of ionization does not. From this we conclude that direct, nonresonant ionization of the ground state competes strongly with the resonant process.

Physical Review AOct 18, 20006 citations

States in a Weak—Near-Resonant Laser

Marvin H. Mittleman

Springer eBooksJan 1, 19820 citations

Complementarity and quantum erasure with dispersive atom-field interactions

Christopher C. Gerry

The "welcher Weg" (which-path) detector as described by Scully et al. [Nature 351, 111 (1991)] employs a pair of initially empty micromaser cavities placed in front of a double-slit apparatus in an atomic interferometer. Laser excited atoms spontaneously emit a photon into either cavity thereby marking the atoms' path and thereby destroying the interference. I propose an alternative method wherein at least one of the cavities is prepared in a coherent state with a strong amplitude. Which-path information is obtained by a nonresonant, dispersive type of atom-field interaction associated with quantum nondemolition measurements. Ground-state atoms passing through the cavity remain in the ground state but impart a phase shift to the cavity fields. Velocity selection is shown to affect the visibility of the fringes. An associated quantum eraser is also discussed.The "welcher Weg" (which-path) detector as described by Scully et al. [Nature 351, 111 (1991)] employs a pair of initially empty micromaser cavities placed in front of a double-slit apparatus in an atomic interferometer. Laser excited atoms spontaneously emit a photon into either cavity thereby marking the atoms' path and thereby destroying the interference. I propose an alternative method wherein at least one of the cavities is prepared in a coherent state with a strong amplitude. Which-path information is obtained by a nonresonant, dispersive type of atom-field interaction associated with quantum nondemolition measurements. Ground-state atoms passing through the cavity remain in the ground state but impart a phase shift to the cavity fields. Velocity selection is shown to affect the visibility of the fringes. An associated quantum eraser is also discussed.

Physical Review AFeb 1, 199622 citations

Nonresonant perturbation of atomic spectra in a light field

G. A. Delone, Nikolai B. Delone, B. A. Zon +2 more

Physics-UspekhiSep 1, 19750 citations

Experimental studies of high-lying Rydberg states in atomic rubidium

Sylvain Liberman, Jacques Pinard

This paper summarizes a long series of experiments that have been done on Rydberg states of Rb. The basic experimental technique that has been used is atomic-beam laser spectroscopy which allows both low-resolution and high-resolution studies. Excitation of Rydberg states is provided by single-photon absorption from a suitably frequency-doubled rhodamine $6G$ tunable laser. Detection is done by field ionization and ion counting. These techniques have allowed us to study the critical ionizing field, which has been found to follow classical, hydrogenic behavior closely. Rydberg states of Rb have been observed from $n=28$ up to $n>100$ . High-resolution spectroscopic studies have led to measurement of the fine structure for $\mathrm{np}$ levels located between $n=28$ and $n=60$ , as well as the isotope shift of the ground state, $\ensuremath{\delta}\ensuremath{\nu}=(172\ifmmode\pm\else\textpm\fi{}15)$ MHz. Anomalies in the intensity ratio of the doublet $5s\ensuremath{-}np$ transitions have been observed and interpreted as relativistic effects. Perturbations by weak and strong dc electric field are reported. In the case of weak electric fields it is possible to evaluate the polarizability. In the case of strong dc electric fields, new phenomena have been observed and analyzed. We also find experimental evidence of selective photoionization in the presence of an appropriate dc electric field, which could have some applications in laser isotope separation. Finally, we give the preliminary results of an experiment on the effect of a strong nonresonant electromagnetic field on high-lying Rydberg states.This paper summarizes a long series of experiments that have been done on Rydberg states of Rb. The basic experimental technique that has been used is atomic-beam laser spectroscopy which allows both low-resolution and high-resolution studies. Excitation of Rydberg states is provided by single-photon absorption from a suitably frequency-doubled rhodamine $6G$ tunable laser. Detection is done by field ionization and ion counting. These techniques have allowed us to study the critical ionizing field, which has been found to follow classical, hydrogenic behavior closely. Rydberg states of Rb have been observed from $n=28$ up to $n>100$. High-resolution spectroscopic studies have led to measurement of the fine structure for $\mathrm{np}$ levels located between $n=28$ and $n=60$, as well as the isotope shift of the ground state, $\ensuremath{\delta}\ensuremath{\nu}=(172\ifmmode\pm\else\textpm\fi{}15)$ MHz. Anomalies in the intensity ratio of the doublet $5s\ensuremath{-}np$ transitions have been observed and interpreted as relativistic effects. Perturbations by weak and strong dc electric field are reported. In the case of weak electric fields it is possible to evaluate the polarizability. In the case of strong dc electric fields, new phenomena have been observed and analyzed. We also find experimental evidence of selective photoionization in the presence of an appropriate dc electric field, which could have some applications in laser isotope separation. Finally, we give the preliminary results of an experiment on the effect of a strong nonresonant electromagnetic field on high-lying Rydberg states.

Physical Review AAug 1, 197969 citations

4s

state and the first excited

4p

state, and find that the amount of population transferred to the excited state as a function of wavelength and intensity shows clear signatures of these resonances. The ionization yield also shows moderate resonant enhancement for intermediate intensities. We can further distinguish between population transfer to and ionization of the

4p

state by using a chirped laser pulse to temporally separate the two processes. We find that the amount of population remaining in the

4p

state at the end of the pulse shows a pronounced sensitivity to the sign of the chirp whereas the total amount of ionization does not. From this we conclude that direct, nonresonant ionization of the ground state competes strongly with the resonant process.

6G

tunable laser. Detection is done by field ionization and ion counting. These techniques have allowed us to study the critical ionizing field, which has been found to follow classical, hydrogenic behavior closely. Rydberg states of Rb have been observed from

n=28

up to

n>100

. High-resolution spectroscopic studies have led to measurement of the fine structure for

\mathrm{np}

levels located between

n=28

and

n=60

, as well as the isotope shift of the ground state, $\ensuremath{\delta}\ensuremath{\nu}=(172\ifmmode\pm\else\textpm\fi{}15)$ MHz. Anomalies in the intensity ratio of the doublet $5s\ensuremath{-}np$ transitions have been observed and interpreted as relativistic effects. Perturbations by weak and strong dc electric field are reported. In the case of weak electric fields it is possible to evaluate the polarizability. In the case of strong dc electric fields, new phenomena have been observed and analyzed. We also find experimental evidence of selective photoionization in the presence of an appropriate dc electric field, which could have some applications in laser isotope separation. Finally, we give the preliminary results of an experiment on the effect of a strong nonresonant electromagnetic field on high-lying Rydberg states.