Deceleration of Metastable \rmLi^+ Beam by Combining Electrostatic Lens and Ion Trap Technique

Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam. We present a deceleration method combining electrostatic lens and ion trap technique, which can effectively decelerate ions to energy below the trapping potential of a typical ion trap. The experiments were performed on metastable 1s2s\,^3\!S_1\,\rm Li^+ ions, and demonstrated that the kinetic energy could easily be reduced from \sim450 eV to a few eV, with the latter being confirmed using the Doppler-shifted fluorescence spectra.