18 research outputs found
Part-per-billion measurement of the electric quadrupole transition isotope shifts between Ca and Ca
We report a precise measurement of the isotope shifts in the SD electric quadrupole transition at 729~nm in the Ca. The measurement has been made via high-resolution laser
spectroscopy of co-trapped ions, finding measured shifts of
2,771,872,467.6(7.6), 5,340,887,394.6(7.8), and 9,990,381,870.0(6.3) Hz between
Caand Ca, respectively. By exciting the two
isotopes simultaneously using frequency sidebands derived from a single laser
systematic uncertainties resulting from laser frequency drifts are eliminated.
This permits far greater precision than similar previously published
measurements in other alkaline-earth systems. The resulting measurement
precision provides a benchmark for tests of theoretical isotope shift
calculations, and also offers a step towards probing New Physics via isotope
shift spectroscopy.Comment: 9 pages, 7 figure
Large spin relaxation rates in trapped submerged-shell atoms
Spin relaxation due to atom-atom collisions is measured for magnetically
trapped erbium and thulium atoms at a temperature near 500 mK. The rate
constants for Er-Er and Tm-Tm collisions are 3.0 times 10^-10 cm^3 s^-1 and 1.1
times 10^-10 cm^3 s^-1, respectively, 2-3 orders of magnitude larger than those
observed for highly magnetic S-state atoms. This is strong evidence for an
additional, dominant, spin relaxation mechanism, electrostatic anisotropy, in
collisions between these "submerged-shell" L > 0 atoms. These large spin
relaxation rates imply that evaporative cooling of these atoms in a magnetic
trap will be highly inefficient.Comment: 10 pages, 3 figure
Part-per-billion measurement of the 4^2S_(1/2)→3^2D_(5/2) electric-quadrupole-transition isotope shifts between ^(42,44,48)Ca^+ and ^(40)Ca^+
We report a precise measurement of the isotope shifts in the 4^2S_(1/2)→3^2D_(5/2) electric quadrupole transition at 729 nm in ^(40−42,44,48)Ca^+. The measurement has been made via high-resolution laser spectroscopy of co-trapped ions, finding measured shifts of 2 771 872 467.6(7.6), 5 340 887 394.6(7.8), and 9 990 381 870.0(6.3) Hz between ^(42,44,48)Ca^+ and ^(40)Ca^+, respectively. By exciting the two isotopes simultaneously, using frequency sidebands derived from a single laser, systematic uncertainties resulting from laser frequency drifts are eliminated. This permits far greater precision than similar previously published measurements in other alkaline-earth-metal systems. The resulting measurement accuracy provides a benchmark for tests of theoretical isotope shift calculations and also offers a step towards probing new physics via isotope shift spectroscopy
Demonstration of integrated microscale optics in surface-electrode ion traps
In ion trap quantum information processing, efficient fluorescence collection
is critical for fast, high-fidelity qubit detection and ion-photon
entanglement. The expected size of future many-ion processors require scalable
light collection systems. We report on the development and testing of a
microfabricated surface-electrode ion trap with an integrated high numerical
aperture (NA) micromirror for fluorescence collection. When coupled to a low NA
lens, the optical system is inherently scalable to large arrays of mirrors in a
single device. We demonstrate stable trapping and transport of 40Ca+ ions over
a 0.63 NA micromirror and observe a factor of 1.9 enhancement in photon
collection compared to the planar region of the trap.Comment: 15 pages, 8 figure
Spatially uniform single-qubit gate operations with near-field microwaves and composite pulse compensation
We present a microfabricated surface-electrode ion trap with a pair of
integrated waveguides that generate a standing microwave field resonant with
the 171Yb+ hyperfine qubit. The waveguides are engineered to position the wave
antinode near the center of the trap, resulting in maximum field amplitude and
uniformity along the trap axis. By calibrating the relative amplitudes and
phases of the waveguide currents, we can control the polarization of the
microwave field to reduce off-resonant coupling to undesired Zeeman sublevels.
We demonstrate single-qubit pi-rotations as fast as 1 us with less than 6 %
variation in Rabi frequency over an 800 um microwave interaction region. Fully
compensating pulse sequences further improve the uniformity of X-gates across
this interaction region.Comment: 14 pages, 8 figure
Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation
Recent advances in quantum information processing with trapped ions have
demonstrated the need for new ion trap architectures capable of holding and
manipulating chains of many (>10) ions. Here we present the design and detailed
characterization of a new linear trap, microfabricated with scalable
complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited
to this challenge. Forty-four individually controlled DC electrodes provide the
many degrees of freedom required to construct anharmonic potential wells,
shuttle ions, merge and split ion chains, precisely tune secular mode
frequencies, and adjust the orientation of trap axes. Microfabricated
capacitors on DC electrodes suppress radio-frequency pickup and excess
micromotion, while a top-level ground layer simplifies modeling of electric
fields and protects trap structures underneath. A localized aperture in the
substrate provides access to the trapping region from an oven below, permitting
deterministic loading of particular isotopic/elemental sequences via
species-selective photoionization. The shapes of the aperture and
radio-frequency electrodes are optimized to minimize perturbation of the
trapping pseudopotential. Laboratory experiments verify simulated potentials
and characterize trapping lifetimes, stray electric fields, and ion heating
rates, while measurement and cancellation of spatially-varying stray electric
fields permits the formation of nearly-equally spaced ion chains.Comment: 17 pages (including references), 7 figure