An investigation of the sympathetic cooling \nmethod for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of \nrf heating rates on the ion temperature, trapping parameters, \nand the number of ions is obtained. New rf heating mechanism \naffecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra \nof the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of \nthe laser cooled Mg $^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and \nthe influence of the rf heating rates on the fluorescence lineshapes \nis also discussed. Cooling of the heavy ( $m=720$ a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg $^+$ ions( $m=24$ a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg $^+$ ion crystal structures at mK temperatures.An investigation of the sympathetic cooling \nmethod for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of \nrf heating rates on the ion temperature, trapping parameters, \nand the number of ions is obtained. New rf heating mechanism \naffecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra \nof the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of \nthe laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and \nthe influence of the rf heating rates on the fluorescence lineshapes \nis also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.

Feb 17, 20050 citations

Spectroscopy of a singly trapped

^{25}

^{+}

ion

^+

ions under different trapping conditions.The ion temperatures are deduced from the measurements, and \nthe influence of the rf heating rates on the fluorescence lineshapes \nis also discussed. Cooling of the heavy (

m=720

a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg

^+

ions(

m=24

a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg

^+

ion crystal structures at mK temperatures.