Selective strong-field enhancement and suppression of ionization with short laser pulses

Abstract

We experimentally demonstrate robust selective excitation and attenuation of atomic Rydberg level populations in sodium vapor (Na i) using intense laser pulses in the strong-field limit $(>{10}^{12}\phantom{\rule{0.16em}{0ex}}\mathrm{W}/\mathrm{c}{\mathrm{m}}^{2})$. Coherent control of the atomic population and related ionization channels is realized for intensities above the over-the-barrier ionization intensity. Moreover, atomic excitation selectivity and high ionization yield are simultaneously achieved without the need to tailor the spectral phase of the laser. A qualitative model confirms that this strong-field coherent control arises through the manifestation of a Freeman resonance.