HIGH-ORDER MULTIPOLE EXCITATION OF A BOUND ELECTRON

The nonlinear resonant response of a bound electron to a time-varying spatially inhomogeneous electric field was studied experimentally. By use of the artificial atom ''geonium'' (an electron bound in a Penning trap), we observed up to ninth-order multipole (pentacosiododecapole) coherent excitation of the electron's magnetron motion, and up to thi rd-order (octupole) excitation of the cyclotron motion. Also, by apply ing two fields simultaneously, we have observed coherent stimulated Ra man excitation of the electron's motion.