Diffusionlike Aspects of Multiphoton Absorption in Electrically Polarized Highly Excited Hydrogen Atoms

Abstract

We have observed microwave transitions of overall order up to 16 in hydrogen atoms initially in $n=60\mathrm{}$ lowest-energy Stark states. Increases in $n$ as large as 4 occur with little change in the electric quantum number $n_e$. Thus hydrogen atoms electrically polarized along the direction of a strong linearly polarized microwave electric field respond one-dimensionally to this field by maintaining their polarization. At some microwave frequencies the final-state $n$ distribution is smooth above threshold field values estimated for stochastic transitions.