Intense Field Detachment of a Weakly Bound Electron: Stabilization and Its Breakdown

We study the problem of an electron in a zero range potential interacting with an elliptically-polarized, monochromatic laser field. We employ the method of quasistationary quasienergy states for the calculation of total and partial (n-photon) ionization rates. Our analytical and numerical results show that the action of a superstrong monochromatic laser field on the weakly-bound electron is equivalent to that of a strong static electric field. Also, in contrast with predictions of a number authors on the lack of stabilization for ionization from a short-range potential, our analysis demonstrates the existence of a stabilization-like regime at above-threshold frequencies but only for a limited interval of laser intensities.