Dynamic Stark Splitting of Multiphoton Absorption Resonances

Sumit K. Basu, T. Pramila, D. Kanjilal

Carlos A Trallero-Herrero, David Cardoza, Thomas C. Weinacht +1 more

We show that coherent control of multiphoton transitions is possible in the strong field limit, even in the presence of large dynamic Stark shifts. By tailoring the phase of an ultrafast laser pulse, one can compensate for the dynamic Stark shift during the atom-field interaction to achieve efficient population transfer in two-photon absorption. Numerical simulations for atomic sodium reveal efficient population transfer from the $\ensuremath{\mid}3s⟩$ ground state to the $\ensuremath{\mid}4s⟩$ excited state using an appropriately shaped ultrafast laser pulse. The theory and simulations provide insight into coherent control of more complicated multiphoton processes.

Theodor W. Hänsch, R. Keil, Alfred Schabert +2 more

P Kruit, J. Kimman, Marnix J. van der Wiel

The energy spectrum of electrons produced by multiphoton ionisation of xenon atoms has been measured, using a new type of electron energy analyser with an acceptance angle of 2 pi sr. Absorption of additional photons above the minimum number required for ionisation has been observed in the non-resonant as well as in the resonant multiphoton ionisation process. In the resonant proces the AC Stark shift is used to link wavelength detuning to the light intensity, in order to find the probability of extra photon absorption as a function of light intensity.

A. T. Georges, P. Lambropoulos

The authors investigate the saturation and Stark splitting of an atomic transition in (i) a phase-diffusion field and (ii) a chaotic field of arbitrary bandwidth. The theory takes into account the infinite sequence of field-correlation functions. It is shown that a chaotic field is less effective than a phase-diffusion field in saturating a single- or multiphoton transition. This is contrary to the weak-field case, where the intensity fluctuations and the associated photon bunching make the chaotic field more effective in exciting a multiphoton transition. It is also shown that the Stark splitting of an atomic transition, as observed in double resonance, is influenced dramatically by the intensity fluctuations in the chaotic field.

Pierre Agostini, P. Breger, Anne L’Huillier +4 more