Excitonic Floquet states in quantum wire

We use Floquet theory to study the effects of laser light coupling to an electron-hole pair confined in a quantum wire. Fast oscillating electric field directed along the wire continuously displaces spatially the electron and hole in opposite directions, that influences on effective time-averaged electrostatic interaction by shallowing its minimum. Renormalization of binding energy leaves distinctive stamp in Floquet energy spectra because both the ponderomotive and confining energies may be neglected in considered perturbative regime. Due to renormalization of binding energy the blueshifted dressed exciton's energy states form crossings and avoided crossings in energy spectra while their oscillator strengths are gradually reduced for increasing laser intensity, these features are strongly dependent on spatial sizes of wire. Discussed properties of Floquet exciton confined in QWr could potentially be used to build the fast terahertz optical bright-dark state switcher or to realize Floquet-Landau-Zener transition.