Analytic expression of the ionization probability about 3+1 resonance enhanced multi-photon ionization (REMPI) process is deduced with the theory of rate equation, which implies the interaction of photon and material. Based on the expressions, the influence of laser intensity, laser pulse duration and spontaneous radiation lifetime on the ionization probability is analyzed theoretically. It is found that the ionization probability increases with laser intensity and laser pulse duration until gets to saturation. After that, the ionization probability will oscillate around the saturation value if laser intensity increases further. The amplitude of oscillation increases with laser intensity at first, and then it will decrease even get to zero after a maximum peak comes out. We attribute the appearance of the oscillation to the phenomena of quantum coherence caused by the splitting of energy level in strong laser field. As to the fact that the ionization probability becomes to zero with the increase of laser intensity, it indicates that laser intensity is strong enough so as to make the neutral particles getting to the region of ionization suppression. It is also found that the variation of ionization probability with spontaneous radiation lifetime is far smaller than the one with ionization rate. So the influence of the spontaneous radiation lifetime on ionization probability could be ignored.Analytic expression of the ionization probability about 3+1 resonance enhanced multi-photon ionization (REMPI) process is deduced with the theory of rate equation, which implies the interaction of photon and material. Based on the expressions, the influence of laser intensity, laser pulse duration and spontaneous radiation lifetime on the ionization probability is analyzed theoretically. It is found that the ionization probability increases with laser intensity and laser pulse duration until gets to saturation. After that, the ionization probability will oscillate around the saturation value if laser intensity increases further. The amplitude of oscillation increases with laser intensity at first, and then it will decrease even get to zero after a maximum peak comes out. We attribute the appearance of the oscillation to the phenomena of quantum coherence caused by the splitting of energy level in strong laser field. As to the fact that the ionization probability becomes to zero with the increase of laser intensity, it indicates that laser intensity is strong enough so as to make the neutral particles getting to the region of ionization suppression. It is also found that the variation of ionization probability with spontaneous radiation lifetime is far smaller than the one with ionization rate. So the influence of the spontaneous radiation lifetime on ionization probability could be ignored.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIENov 29, 20120 citations

Resonance phenomena in saturation of absorption by laser radiation

Vladilen S Letokhov, V. P. Chebotaev

Uspekhi Fizicheskih NaukJan 1, 19745 citations

Theory of Laser Oscillation

Kōichi Shimoda

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19860 citations

Coherent interaction of an ultrashort zero-area laser pulse with a Morse oscillator

Szczepan Chelkowski, André D. Bandrauk

Dissociation probabilities, energy absorption, and ground-state populations are calculated numerically for interaction of a Morse oscillator with a resonant ultrashort ( ${\mathit{t}}_{\mathit{p}}$ ${10}^{\mathrm{\ensuremath{-}}12}$ sec) intense laser pulse as a function of intensity and pulse area in order to investigate the sensitivity of coherence phenomena to delocalization and chaos in molecule-radiation field systems. It is concluded that a zero-area pulse can reduce considerably energy absorbed by a molecule as well as dissociation probabilities for intensities below and near the chaotic region. It is found that the two-level model (describing the interaction of light resonant with the ground to first excited level transition) works well up to the intensity ${10}^{12}$ W/ ${\mathrm{cm}}^{2}$ , above which transitions to higher levels must be considered.Dissociation probabilities, energy absorption, and ground-state populations are calculated numerically for interaction of a Morse oscillator with a resonant ultrashort (${\mathit{t}}_{\mathit{p}}$${10}^{\mathrm{\ensuremath{-}}12}$ sec) intense laser pulse as a function of intensity and pulse area in order to investigate the sensitivity of coherence phenomena to delocalization and chaos in molecule-radiation field systems. It is concluded that a zero-area pulse can reduce considerably energy absorbed by a molecule as well as dissociation probabilities for intensities below and near the chaotic region. It is found that the two-level model (describing the interaction of light resonant with the ground to first excited level transition) works well up to the intensity ${10}^{12}$ W/${\mathrm{cm}}^{2}$, above which transitions to higher levels must be considered.

Physical Review AJun 1, 199048 citations

Theory of Laser Oscillation

Kōichi Shimoda

Springer series in optical sciences/SPringer series in optical sciencesJan 1, 19840 citations

Effective trapping of cold atoms using dipole and radiative forces in an optical trap

Taro Mashimo, Masashi Abe, 賢東條

We report on the stable effective trapping of cold rubidium atoms by a method for a single optical trap in the near-optical resonant regime. An optical trap with the near-optical resonance condition consists of not only the dipole but also the radiative forces, while a trap using a far-off resonance dominates only the dipole force. We measure the spatial behaviors of the center-of-mass positions and the loading efficiencies of the trapped atoms in the near-optical resonant trap, by changing the detuning over the range of $\ensuremath{-}0.373$ to $\ensuremath{-}2.23$ THz from the ${\mathrm{D}}_{2}$ resonance. The time dependence of the spatial behavior in the trap indicates that the suitable positions for stably holding atoms are altered because the equilibrium condition between the optical dipole and the radiative forces depends on the trap laser detuning. The stable position, which is not a primary position of focus in the Gaussian beam optics, depends only on the laser detuning due to the change in the radiative force, while it is independent of the change in the laser intensity, which results in a balance between the radiative and dipole forces.We report on the stable effective trapping of cold rubidium atoms by a method for a single optical trap in the near-optical resonant regime. An optical trap with the near-optical resonance condition consists of not only the dipole but also the radiative forces, while a trap using a far-off resonance dominates only the dipole force. We measure the spatial behaviors of the center-of-mass positions and the loading efficiencies of the trapped atoms in the near-optical resonant trap, by changing the detuning over the range of $\ensuremath{-}0.373$ to $\ensuremath{-}2.23$ THz from the ${\mathrm{D}}_{2}$ resonance. The time dependence of the spatial behavior in the trap indicates that the suitable positions for stably holding atoms are altered because the equilibrium condition between the optical dipole and the radiative forces depends on the trap laser detuning. The stable position, which is not a primary position of focus in the Gaussian beam optics, depends only on the laser detuning due to the change in the radiative force, while it is independent of the change in the laser intensity, which results in a balance between the radiative and dipole forces.

arXiv:1902.00258Physical Review ADec 23, 20193 citations

Dissociation probabilities, energy absorption, and ground-state populations are calculated numerically for interaction of a Morse oscillator with a resonant ultrashort (

{\mathit{t}}_{\mathit{p}}

${10}^{\mathrm{\ensuremath{-}}12}$ sec) intense laser pulse as a function of intensity and pulse area in order to investigate the sensitivity of coherence phenomena to delocalization and chaos in molecule-radiation field systems. It is concluded that a zero-area pulse can reduce considerably energy absorbed by a molecule as well as dissociation probabilities for intensities below and near the chaotic region. It is found that the two-level model (describing the interaction of light resonant with the ground to first excited level transition) works well up to the intensity

{10}^{12}

{\mathrm{cm}}^{2}

, above which transitions to higher levels must be considered.

{\mathrm{D}}_{2}

resonance. The time dependence of the spatial behavior in the trap indicates that the suitable positions for stably holding atoms are altered because the equilibrium condition between the optical dipole and the radiative forces depends on the trap laser detuning. The stable position, which is not a primary position of focus in the Gaussian beam optics, depends only on the laser detuning due to the change in the radiative force, while it is independent of the change in the laser intensity, which results in a balance between the radiative and dipole forces.