Layout image showing (a) trap design, (b) individual die level, and (c) the wafer layout. The lightly shaded regions represent the first layer which is used for routing and the darker shaded regions represent the second layer, which are the protruding trap features.
(a) Optical and (b) scanning electron microscope (SEM) images showing trap features. Each post has electrical connection leads that are connected to bond pads on perimeter of each die. To reduce exposed insulating substrate area, the die used in the experiment did not have the logos.
Optical micrograph of the trap used in the experiments. The paths of the laser beams are overlaid as arrows. The BD, BDD, RD, and PI beams are co-linear and focused at ∼60 μm above the trap, coming up, out of the plane at an angle of ∼4° from right to left. The BR and RR beams are parallel to the plane of the trap.
Stylus-trap chip mounted in the vacuum chamber. One of the five compensation-post filter capacitors can be seen at the bottom right. The 25Mg evaporator is in the background.
Acousto-optic modulator setup used to generate the five Doppler and Raman cooling lasers for 25Mg+ from a single 279.67-nm source. The input −600 MHz (upper left) and output detunings (right) are referenced to the 2S1/2 |3, −3⟩ to 2P3/2 |4, −4⟩ transition. All detunings and AOM frequency shifts have units of MHz. GLP: Glan-laser prism
Simplified level diagram of 25Mg+. The left column shows the electronic levels without hyperfine structure. The next column shows the energy levels including hyperfine structure, at zero magnetic field. The right side of the figure shows the relevant Zeeman sublevels in a magnetic field of 1.0 mT. Solid arrows represent transitions addressed with lasers, while dashed arrows represent microwave-addressed transitions. Dotted arrows represent frequency separations. The nominal polarizations of the laser beams are indicated with the beam labels.
Frequency sweep of the BR laser to show the sidebands for the MSS and MAS transitions after 45 cycles of Raman cooling. The fitted sideband amplitudes 21 indicate that the ion is cooled to an average motional quanta of ⟨n⟩ = 0.34 ± 0.07. The frequencies of the sidebands are shifted so that the curves overlap. The background of the sidebands is large because of the high spontaneous emission rates from the relatively small Raman detunings. 18
Plot of the average motional quanta as a function of wait time after applying 45 cycles of Raman cooling. The heating rate of 387 ± 15 quanta/s was measured at a mode frequency of 4 MHz and an ion height of 62 μm.
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