Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam.
Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam.
The field of atom chips is a relatively new area of research which is rapidly becoming of great interest to the scientific community. It started out as a small branch of cold atom physics which has quickly grown into a multidisciplinary\nsubject. It now encompasses topics from fundamental atomic and quantum theory, optics and laser science, to the engineering of ultra sensitive sensors.\n\nIn this thesis the first steps are taken towards a truly integrated atom chip device for real world applications. Multiple devices are presented that allow the trapping, cooling, manipulation and counting of atoms. Each device presents a new component required for the integration and miniaturisation of atom chips\ninto a single device, capable of being used as a sensor.\n\nInitially, a wire trap was created capable of trapping and splitting a cloud of BoseEinstein condensate (BEC) for use in atom interferometry. Using this chip a BEC has been successfully created, trapped and coherent splitting of this cloud has been achieved.\n\nSubsequently, the integration and simplification of the initial trapping process was approached. In all the experiments to date, atoms are initially collected from a warm vapour by a magneto-optical trap (MOT). This thesis presents a new approach in which microscopic pyramidal MOTs’ are integrated into the chip itself. This greatly reduces the number of optical components and helps to simplify the process significantly.\n\nAlso presented is a method for creating a planar-concave micro-cavity capable of single atom detection. One such cavity consists of a concave mirror fabricated in silicon and the planar tip of an optical fibre. The performance of the resonators\nis highly dependent on the surface roughness and shape profile of the concave mirrors therefore a detailed study into the fabrication technique and its effects on these parameters was undertaken. Using such cavities single atom detection has been shown to be possible. These cavities have also been sccessfully integrated into an atom wire guide.\n\nFinally a co-sputtered amorphous silicon/titanium (a-Si/Ti) nanocomposite material was created and studied for its use as a novel structural material. This material is potentially suitable for integrated circuitry (IC)/Micro-electromechanical-\nsystems (MEMS) integration. The material’s electrical and\nstructural properties were investigated and initial results suggest that a-Si/Ti has the potential to be a compelling structural material for future IC/MEMS integration.\n\nTo build all of these devices, a full range of standard microfabrication techniques was necessary as well as some non standard processes that required considerable process development such as the electrochemical deposition.\n\nThis thesis presents a tool box of fabrication techniques for creating various components capable of different tasks that can be integrated into a single device. Each component has been successfully demonstrated in laboratory conditions. This represents a significant step toward a real world atom chip device.
Abstract Micro- and increasingly, nano-fabrication have enabled the miniaturization of atomic devices, from vapor cells to atom chips for Bose-Einstein condensation. Here we present microfabricated planar devices for thermal atomic beams. Etched microchannels were used to create highly collimated, continuous rubidium atom beams traveling parallel to a silicon wafer surface. Precise, lithographic definition of the guiding channels allowed for shaping and tailoring the velocity distributions in ways not possible using conventional machining. Multiple miniature beams with individually prescribed geometries were created, including collimated, focusing and diverging outputs. A “cascaded” collimator was realized with 40 times greater purity than conventional collimators. These localized, miniature atom beam sources can be a valuable resource for a number of quantum technologies, including atom interferometers, clocks, Rydberg atoms, and hybrid atom-nanophotonic systems, as well as enabling controlled studies of atom-surface interactions at the nanometer scale.
Micro- and increasingly, nano-fabrication have enabled the miniaturization of atomic devices, from vapor cells to atom chips for Bose-Einstein condensation. Here we present microfabricated planar devices for thermal atomic beams. Etched microchannels were used to create highly collimated, continuous rubidium atom beams traveling parallel to a silicon wafer surface. Precise, lithographic definition of the guiding channels allowed for shaping and tailoring the velocity distributions in ways not possible using conventional machining. Multiple miniature beams with individually prescribed geometries were created, including collimated, focusing and diverging outputs. A "cascaded" collimator was realized with 40 times greater purity than conventional collimators. These localized, miniature atom beam sources can be a valuable resource for a number of quantum technologies, including atom interferometers, clocks, Rydberg atoms, and hybrid atom-nanophotonic systems, as well as enabling controlled studies of atom-surface interactions at the nanometer scale.
Various regimes of the loading of a magneto-optical trap formed near an atom chip, such as loading from thermal atomic vapors and from a low-velocity atomic beam, have been studied on an example of 87Rb atoms. The possibility of controlling the loading of the magneto-optical trap by spatially controlling the atomic beam has been demonstrated. This has made it possible to increase the loading rate of atoms into the magneto-optical trap with keeping ultrahigh vacuum near the atom chip. The maximum number of atoms in the magneto-optical trap at optimal loading regimes is 4.9 × 107. In this case, the measured lifetime of atoms in the magneto-optical trap is 4.1 s.
The fine control of a neutral atomic beam by radiation pressure has opened a new field called atom lithography. In particular, a direct writing method, which focuses an atomic beam with a standing-wave light field into narrow lines, has been demonstrated. A velocity-controlled and isotope-selected atomic beam is essential for improving the performance of this lithography method. An atomic deflection technique using radiation pressure is indispensable for producing such an atomic beam. Here we report on an atomic beam guide using a one-dimensional magneto-optical trap (1D-MOT). First we decelerate atoms whose velocities lie in the range between 250 and 320 m/s. A diode laser (780 nm) is used as the light source for deceleration and its injection current is modulated at 2 MHz. Then the decelerated beam is deflected by a tilted 1D-MOT, which consists of four copper rods and four rectangular mirrors.
Ultracold atoms can be manipulated using microfabricated devices known as atom chips. These have significant potential for applications in sensing, metrology, and quantum information processing. To date, the chips are loaded by transfer of atoms from an external macroscopic magnetooptical trap (MOT) into microscopic traps on the chip. This transfer involves a series of steps, which complicate the experimental procedure and lead to atom losses. In this paper, we present a design for integrating a MOT into a silicon wafer by combining a concave pyramidal mirror with a square wire loop. We describe how an array of such traps has been fabricated, and we present magnetic, thermal, and optical properties of the chip.