We demonstrate fast loading of our trapped ion quantum computer using a compact 2D Magneto-Optical Trap (MOT). We characterize the MOT loading system by direct measurements of the cold atomic beam produced thereby. We load both ytterbium and barium ions two orders of magnitude faster than using a conventional oven loading method with negligible impact on vacuum performance in the trapped ion region. These improvements to loading address one of the concerns in scaling our QCCD architecture up to large Qubit numbers.
We demonstrate fast loading of our trapped ion quantum computer using a compact 2D Magneto-Optical Trap (MOT). We characterize the MOT loading system by direct measurements of the cold atomic beam produced thereby. We load both ytterbium and barium ions two orders of magnitude faster than using a conventional oven loading method with negligible impact on vacuum performance in the trapped ion region. These improvements to loading address one of the concerns in scaling our QCCD architecture up to large Qubit numbers.
In order to scale up quantum computing, a scalable experimental architecture is needed, with the trapped-ion quantum computing platform; this has led to the implementation of surface ion traps. Despite being more performant than the older linear Paul trap design, they suffer from a lower trap depth. This reduces not only the probability of ion capture but also increases the dependency on the vacuum quality. Therefore, clean, cold, compact and robust atom sources are needed for the next generation of ion-trap-based quantum computers. Within the scope of this thesis, a repumped 3D magneto-optical trap (MOT) for the 40Ca species with a loading time of 1 s was demonstrated. Furthermore, we have also shown the ability to measure the performance of cold atom sources by resolving different Calcium isotopes via photoionisation detection. Finally, we demonstrate a novel and compact pyramid MOT design, which was tested and verified for 40Ca. The presented magneto-optical trap design can be integrated into other quantum computing experiments.
We demonstrate direct loading of a strontium (Sr) magneto-optical trap (MOT) from a thermal atomic beam in a single-chamber vacuum system. The MOT operates without a Zeeman slower, a slowing laser, a two-dimensional MOT, or differential pumping, while the entire system is maintained in the ultra-high-vacuum regime by a single ion pump. At an oven temperature of 395 °C, the MOT captures up to 107 88Sr atoms with a loading rate of 107 atoms s-1, while sustaining a background gas pressure of 1 × 10-9 Torr. At this oven temperature, the MOT lifetime limited by collisions with background gas is ∼5s, with the atom number primarily constrained by light-assisted two-body collisions. Eliminating differential pumping and precooling stages significantly reduces the system's size, weight, and power requirements, providing a robust and practical platform for field-deployable and spaceborne optical lattice clocks, as well as a variety of other applications requiring compact ultracold atom sources.
We present a high-flux source of cold strontium atoms based on a two-dimensional magneto-optical trap (2D MOT) and a Zeeman slower. We use the source to load a 3D MOT in a separate science chamber, observing a loading rate of 4×1010 atoms/s—to our knowledge, the highest reported loading flux for strontium. To characterize the vacuum pressure in the science chamber, we load the atoms into a magnetic trap and measure a lifetime of between 8 and 24 s, depending on the oven temperature. Finally, we characterize the atom flux and velocity distributions from the oven and from the 2D MOT source, finding reasonable agreement with models in the free molecular flow regime. Our results show that it is possible to readily produce a cold strontium flux at comparable levels to those of alkali species, at oven temperatures compatible with long-term operation, and at vacuum pressures suitable for state-of-the-art quantum experiments. We make our design available at no cost to benefit researchers in the quantum community.
A compact cold atom beam source based on a multistage two-dimensional magneto-optical trap (MOT) has been demonstrated and characterized. The multiple-stage design greatly reduces the overall size of the source apparatus while providing a high flux of atoms. The cold atom beam was used to load a separate MOT in ultrahigh vacuum, and we obtained an actual trap loading rate of 1.5 x 109 atoms/s while using only 20 mW of total laser power for the source. The entire source apparatus, including optics, can fit into a 4 cm x 4 cm x 13 cm volume.
We report on a scheme for loading dysprosium atoms into a narrow-line three-dimensional magneto-optical trap (3D MOT). Our approach replaces the conventional Zeeman slower with a two-dimensional (2D) MOT operating on the broad 421-nm line to create a high-flux beam of slow atoms. Even in the absence of a push beam, we demonstrate efficient loading of the 3D MOT, which operates on the narrower 626-nm intercombination line. Adding push beams working at either 421 nm or 626 nm, significant enhancement of the loading rate is achieved. We reach the best performance, with an enhancement factor of 3.6, using a push beam red-detuned to the 626-nm line. With loading rates greater than 108atoms/s achieved at a moderate oven reservoir temperature of ${800}^{\ensuremath{\circ}}\phantom{\rule{0.16em}{0ex}}\mathrm{C}$, our method offers similar or greater performance than Zeeman-slower-based systems. Our 2D-MOT-based approach constitutes a promising first step towards state-of-the-art quantum gas experiments with several advantages over the Zeeman-slower-based setup and is readily adaptable to other open-shell lanthanides.
We demonstrate efficient loading of an Yb three-dimensional magneto-optical trap (3D MOT) on the 1S0 → 1P1 transition. The experiment employs a two-dimensional magneto-optical trap (2D MOT) as an efficient cold atom source. Through optimization of the 2D MOT, auxiliary Zeeman slower, and push beam parameters that govern atomic capture, we achieve an atomic loading rate of 5 × 106 atoms/s in the 3D MOT, with approximately ∼107 trapped atoms. Our experimental results confirm the successful transfer of a substantial number of atoms from the 2D region to the science chamber via the push beam, providing an experimental foundation for subsequent implementation of narrow-line MOT and two-color MOT.