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We demonstrate experimentally the Doppler cooling of 40Ca+ ions using the s1/2 → D3/2 electric quadrupole transition, in which the scattering light that is much different from the exciting light makes it possible to collect background-free fluorescence. The idea excluding 397nm excitation has the advantage of high-sensitivity detection and only employs lasers in red and infrared wavelengths, which should be practical for trapped-ion quantum information processing. [ABSTRACT FROM AUTHOR]

40Ca+ ions are successfully confined, under the cooling of a red-detuned laser, in a home-built microscopic surface-electrode (MSE) trap. With all electrodes deposited on a low-rf-loss substrate, our 500- µm-scale MSE trap is designed involving three potential wells and manufactured by the standard technique of the printed circuit board. Both linear and two-dimensional crystals of 40Ca+ are observed in the trap after preliminary micromotion compensation is carried out. The development of the MSE trap aims at large-scale trapped-ion quantum information processing. [ABSTRACT FROM AUTHOR]

We investigate the spectra of the electric quadrupole 42S1/2→32D5/2 transitions in a single 40Ca+ ion confined in a home-built linear trap. We probe the transitions with an ultra-narrow bandwidth laser at 729 nm. In a weak magnetic field, the quadrupole transition splits into ten components with the maximal line strength proportional to their squared Clebsch—Gordan factors. In a magnetic field of the order of Gauss, the observed equidistant sideband reflects the Zeeman substructure modulated by the quantized oscillation due to the secular motion in the trap. The temperature of the trapped ion can be determined by the envelope of the sideband spectrum. We also demonstrate the Rabi oscillation in a carrier transition after the ion has been Doppler cooled, which can be fitted by the model with the thermal state of motion. [ABSTRACT FROM AUTHOR]