We study the motion of a cold atom in a frequency-modulated standing laser wave. If the detuning between the atomic electronic transition and the field is large, the atom moves in a modulated optical potential demonstrating known classical nonlinear effects such as chaos and nonlinear resonances. If the atom-field detuning is small, then two optical potentials emerge in the system, and the atom performs Landau-Zener (LZ) tunnelings between them. It is a radically non-classical behavior. However, we show that classical nonlinear structures in system's phase space (KAM-tori and chaotic layers) survive. Quantum effect of LZ tunnelings only induces small random jumps of trajectories between these structures (dynamical tunneling).We study the motion of a cold atom in a frequency-modulated standing laser wave. If the detuning between the atomic electronic transition and the field is large, the atom moves in a modulated optical potential demonstrating known classical nonlinear effects such as chaos and nonlinear resonances. If the atom-field detuning is small, then two optical potentials emerge in the system, and the atom performs Landau-Zener (LZ) tunnelings between them. It is a radically non-classical behavior. However, we show that classical nonlinear structures in system's phase space (KAM-tori and chaotic layers) survive. Quantum effect of LZ tunnelings only induces small random jumps of trajectories between these structures (dynamical tunneling).

arXiv:1401.2156Jan 9, 20140 citations

Dynamics of Excited States of an Atom Interacting with Strong Laser Fields

Constantine Mavroyannis

Springer eBooksJan 1, 19860 citations

Photoassociation dynamics driven by a modulated two-color laser field

Wei Zhang, Zeyu Zhao, Ting Xie +3 more

Photoassociation (PA) dynamics of ultracold cesium atoms steered by a modulated two-color laser field $\phantom{\rule{4pt}{0ex}}E(t)={E}_{0}f(t)\mathrm{cos}(\frac{2\ensuremath{\pi}}{{T}_{p}}\ensuremath{-}\ensuremath{\varphi})\mathrm{cos}({\ensuremath{\omega}}_{L}t)$ is investigated theoretically by numerically solving the time-dependent Schr\"odinger equation. The PA dynamics is sensitive to the phase of envelope (POE) $\ensuremath{\varphi}$ and the period of the envelope ${T}_{p}$ , which indicates that it can be controlled by varying POE $\ensuremath{\varphi}$ and period ${T}_{p}$ . Moreover, we introduce the time- and frequency-resolved spectrum to illustrate how the POE $\ensuremath{\varphi}$ and the period ${T}_{p}$ influence the intensity distribution of the modulated laser pulse and hence change the time-dependent population distribution of photoassociated molecules. When the Gaussian envelope contains a few oscillations, the PA efficiency is also dependent on POE $\ensuremath{\varphi}$. The modulated two-color laser field is available in the current experiment based on laser mode-lock technology.Photoassociation (PA) dynamics of ultracold cesium atoms steered by a modulated two-color laser field $\phantom{\rule{4pt}{0ex}}E(t)={E}_{0}f(t)\mathrm{cos}(\frac{2\ensuremath{\pi}}{{T}_{p}}\ensuremath{-}\ensuremath{\varphi})\mathrm{cos}({\ensuremath{\omega}}_{L}t)$ is investigated theoretically by numerically solving the time-dependent Schr\"odinger equation. The PA dynamics is sensitive to the phase of envelope (POE) $\ensuremath{\varphi}$ and the period of the envelope ${T}_{p}$, which indicates that it can be controlled by varying POE $\ensuremath{\varphi}$ and period ${T}_{p}$. Moreover, we introduce the time- and frequency-resolved spectrum to illustrate how the POE $\ensuremath{\varphi}$ and the period ${T}_{p}$ influence the intensity distribution of the modulated laser pulse and hence change the time-dependent population distribution of photoassociated molecules. When the Gaussian envelope contains a few oscillations, the PA efficiency is also dependent on POE $\ensuremath{\varphi}$. The modulated two-color laser field is available in the current experiment based on laser mode-lock technology.

Physical Review ANov 16, 201113 citations

Quantum motion of laser-driven atoms in a cavity field

Christoph Maschler, Helmut Ritsch

Optics CommunicationsNov 4, 200441 citations

AC Stark effect and fluorescence using modulated laser beams. I. Effect of laser fluctuations and arbitrary relaxation parameters

Ragini Saxena, G. S. Agarwal

The influence of relaxation parameters, as well as temporal fluctuations in the laser field on the modulation rate and phaseshift of the fluorescence from a two-level atom excited by a weakly modulated source is studied in detail. It is shown that, for intense resonant laser fields, the resonance in the modulation rate occurs at the modulation frequency Omega =2 due to the dynamical Stark splitting and has a width equal to 1 / 2 (T 1 -1 +T 2 -1 ). When temporal fluctuations of the exciting laser field are taken into account, the phaseshift of the scattered light is found to be strongly dependent on the bandwidth of the exciting source, as well as the frequency of modulation; hence experimental results on the determination of the lifetime by the phaseshift method have to be interpreted carefully. Numerical results for the modulation rates and phaseshift at different field strengths and various values of T 1 -1 , T 2 -1 , Delta laser bandwidth and Doppler broadening are presented.The influence of relaxation parameters, as well as temporal fluctuations in the laser field on the modulation rate and phaseshift of the fluorescence from a two-level atom excited by a weakly modulated source is studied in detail. It is shown that, for intense resonant laser fields, the resonance in the modulation rate occurs at the modulation frequency Omega =2 due to the dynamical Stark splitting and has a width equal to 1 / 2 (T 1 -1 +T 2 -1 ). When temporal fluctuations of the exciting laser field are taken into account, the phaseshift of the scattered light is found to be strongly dependent on the bandwidth of the exciting source, as well as the frequency of modulation; hence experimental results on the determination of the lifetime by the phaseshift method have to be interpreted carefully. Numerical results for the modulation rates and phaseshift at different field strengths and various values of T 1 -1 , T 2 -1 , Delta laser bandwidth and Doppler broadening are presented.

Journal of Physics B Atomic and Molecular PhysicsJun 28, 197916 citations

Dynamics of an n level system of atoms interacting with laser fields

Kozo Fujii

Journal of Mathematical SciencesAug 1, 20085 citations

{T}_{p}

, which indicates that it can be controlled by varying POE $\ensuremath{\varphi}$ and period

{T}_{p}

. Moreover, we introduce the time- and frequency-resolved spectrum to illustrate how the POE $\ensuremath{\varphi}$ and the period

{T}_{p}

influence the intensity distribution of the modulated laser pulse and hence change the time-dependent population distribution of photoassociated molecules. When the Gaussian envelope contains a few oscillations, the PA efficiency is also dependent on POE $\ensuremath{\varphi}$. The modulated two-color laser field is available in the current experiment based on laser mode-lock technology.