A nonperturbative semiclassical theory is presented for the treatment of four-wave mixing (FWM) in a four-level system. This treatment is based on a transformation to a generalized rotating frame followed by a numerical diagonalization of the resulting time-independent Hamiltonian. For strong fields, all resonant frequencies are shifted from the atomic (molecular) frequencies. Lines are split up in a way similar to the ac Stark effect for a two-level system, and for even stronger fields, the effect of stirring is observed for the first time in four-wave mixing. In addition, a new extra resonance appears which is induced by the saturating field. This field-induced resonance is the new member in the family of extra resonances (pressure induced, or stochastic fluctuation induced), and it should be observed whenever saturating fields interact with a multilevel atomic or molecular system.A nonperturbative semiclassical theory is presented for the treatment of four-wave mixing (FWM) in a four-level system. This treatment is based on a transformation to a generalized rotating frame followed by a numerical diagonalization of the resulting time-independent Hamiltonian. For strong fields, all resonant frequencies are shifted from the atomic (molecular) frequencies. Lines are split up in a way similar to the ac Stark effect for a two-level system, and for even stronger fields, the effect of stirring is observed for the first time in four-wave mixing. In addition, a new extra resonance appears which is induced by the saturating field. This field-induced resonance is the new member in the family of extra resonances (pressure induced, or stochastic fluctuation induced), and it should be observed whenever saturating fields interact with a multilevel atomic or molecular system.

Physical Review AMar 1, 198729 citations

Extra sub-Doppler lines in the vicinity of the third-resonance 6 S -8 P transition of atomic Cs attributed to optically induced Cs dimers

Thierry Passerat de Silans, Isabelle Maurin, Athanasios Laliotis +2 more

We report on the observation of additional sub-Doppler lines in a saturated absorption experiment when exploring the vicinity of the $6{S}_{1/2}\ensuremath{-}8{P}_{3/2}$ transition of Cs (\ensuremath{\lambda}$=$388 nm). These additional lines are observed only under a relatively strong irradiation of both the pump and the probe beams. Extra narrow lines are also observed in copropagating nonlinear spectroscopy, and around the lines of the V-type three-level system $8{P}_{3/2}\ensuremath{-}6{S}_{1/2}\ensuremath{-}8{P}_{1/2}$ (${\ensuremath{\lambda}}_{1}$$=$388 nm, ${\ensuremath{\lambda}}_{2}$$=$389 nm). We attribute theses additional lines to a probing of high-lying molecular cesium, produced as a result of the optical excitation of Cs atoms, as the low Cs atom density (\ensuremath{\le}10${}^{12} $cm$ {}^{\ensuremath{-}3}$) is unable to populate significantly the dimer states in the condition of thermal equilibrium.We report on the observation of additional sub-Doppler lines in a saturated absorption experiment when exploring the vicinity of the $6{S}_{1/2}\ensuremath{-}8{P}_{3/2}$ transition of Cs (\ensuremath{\lambda}$=$388 nm). These additional lines are observed only under a relatively strong irradiation of both the pump and the probe beams. Extra narrow lines are also observed in copropagating nonlinear spectroscopy, and around the lines of the V-type three-level system $8{P}_{3/2}\ensuremath{-}6{S}_{1/2}\ensuremath{-}8{P}_{1/2}$ (${\ensuremath{\lambda}}_{1}$$=$388 nm, ${\ensuremath{\lambda}}_{2}$$=$389 nm). We attribute theses additional lines to a probing of high-lying molecular cesium, produced as a result of the optical excitation of Cs atoms, as the low Cs atom density (\ensuremath{\le}10${}^{12}$cm${}^{\ensuremath{-}3}$) is unable to populate significantly the dimer states in the condition of thermal equilibrium.

Physical Review AApr 6, 20115 citations

Narrow Nonlinear Resonances in Spectroscopy

Vladilen S Letokhov, Veniamin P. Chebotayev

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19770 citations

Line Shape Analysis of Ultracold Heteronuclear Molecular Photoassociation Spectroscopy by Resonance-Enhanced Two-Photon Ionization

Jinpeng Yuan, Zhonghua Ji, Yanting Zhao +4 more

Resonance-enhanced two-photon ionization (RETPI) is a powerful tool in ultracold molecular photoassociation spectroscopy measurement. Using the RETPI, the line shape of ultracold RbCs molecular photoassociation spectroscopy, which contains intensity and full width at half maximum, is measured and analyzed systematically with varied photoassociation laser intensity and ionization laser energy. The saturation of photoassociation spectroscopy at a high ionization laser energy is observed and the suppression phenomenon is observed at high photoassociation laser intensity. The saturation intensity of RbCs molecular photoassociation, the linewidths of excited state molecules in different rovibrational levels at zero photoassociation laser intensity, and two-photon ionization efficiency have been derived from the line shape of photoassociation spectroscopy. The line shape analysis of photoassociation spectroscopy is important for precision spectroscopic analysis.Resonance-enhanced two-photon ionization (RETPI) is a powerful tool in ultracold molecular photoassociation spectroscopy measurement. Using the RETPI, the line shape of ultracold RbCs molecular photoassociation spectroscopy, which contains intensity and full width at half maximum, is measured and analyzed systematically with varied photoassociation laser intensity and ionization laser energy. The saturation of photoassociation spectroscopy at a high ionization laser energy is observed and the suppression phenomenon is observed at high photoassociation laser intensity. The saturation intensity of RbCs molecular photoassociation, the linewidths of excited state molecules in different rovibrational levels at zero photoassociation laser intensity, and two-photon ionization efficiency have been derived from the line shape of photoassociation spectroscopy. The line shape analysis of photoassociation spectroscopy is important for precision spectroscopic analysis.

Journal of the Physical Society of JapanJul 12, 20131 citation

cm

{}^{\ensuremath{-}3}$) is unable to populate significantly the dimer states in the condition of thermal equilibrium.