Laser spectroscopic study of dynamics of laser‐cooled ions in Paul Trap

Laser cooling of ions stored in a radio‐frequency (rf) quadrupole trap has attracted current interest as a powerful technique in the frequency standard application and the study of fundamental physics, such as the strongly coupled plasma. Dynamical behavior of a small number of ions (well below 100), such as the phase transition to the crystal state, has been extensively investigated both experimentally and theoretically. On the other hand, dynamic properties of a relatively large number of ions have not been clarified thus far.