Many proposals for quantum information processing require precise control over the motion of neutral atoms, as in the manipulation of coherent matter waves or the confinement and localization of individual atoms. Patterns of micron-sized wires, fabricated lithographically on a flat substrate, can conveniently produce large magnetic-field gradients and curvatures to trap cold atoms and to facilitate the production of Bose-Einstein condensates. The intent of this paper is to provide the researcher who has access to a standard clean-room enough information to design and fabricate such devices.Many proposals for quantum information processing require precise control over the motion of neutral atoms, as in the manipulation of coherent matter waves or the confinement and localization of individual atoms. Patterns of micron-sized wires, fabricated lithographically on a flat substrate, can conveniently produce large magnetic-field gradients and curvatures to trap cold atoms and to facilitate the production of Bose-Einstein condensates. The intent of this paper is to provide the researcher who has access to a standard clean-room enough information to design and fabricate such devices.

Quantum Information and ComputationJan 1, 200321 citations

Micro-electromagnets for atom manipulation

Marija Drndić, Kent S. Johnson, Joseph H. Thywissen +2 more

Micro-electromagnets for atom manipulation have been constructed, including magnetic mirrors (serpentine patterns) and traps (circular patterns). They consist of planar micron-scale Au wires on sapphire substrates fabricated using lithography and electroplating. At liquid nitrogen or helium temperatures in vacuum the wires support currents of several amperes with current density ∼108 A/cm2 and power dissipation ∼10 kW/cm2, and they produce magnetic fields to 0.3 T and gradients to 103 T/cm. The micro-electromagnet mirror was used to deflect a beam of metastable helium atoms at grazing angles ∼0.5 mrad.Micro-electromagnets for atom manipulation have been constructed, including magnetic mirrors (serpentine patterns) and traps (circular patterns). They consist of planar micron-scale Au wires on sapphire substrates fabricated using lithography and electroplating. At liquid nitrogen or helium temperatures in vacuum the wires support currents of several amperes with current density ∼108 A/cm2 and power dissipation ∼10 kW/cm2, and they produce magnetic fields to 0.3 T and gradients to 103 T/cm. The micro-electromagnet mirror was used to deflect a beam of metastable helium atoms at grazing angles ∼0.5 mrad.

Applied Physics LettersJun 1, 1998109 citations

Efficient loading of a magnetic waveguide on an atom chip

Peter D. D. Schwindt, Eric Cornell, T. Kishimoto +2 more

We demonstrate efficient loading of neutral atoms into a magnetic waveguide produced by the magnetic fields of microfabricated current-carrying conductors. The lithographically patterned conductors on this ``atom chip'' can be used to make a variety of guiding and trapping structures for manipulating cold atoms and Bose-Einstein condensates. A three-chamber vacuum apparatus collects atoms in a magneto-optical trap, precools them via evaporative cooling, and delivers them to the final chamber containing the atom chip. We describe in detail how the precooled atomic cloud is transferred from a macroscopic magnetic Ioffe-Pritchard trap to the microscopic magnetic waveguide on the atom chip $21\phantom{\rule{0.3em}{0ex}}\mathrm{cm}$ away. Permanent magnets provide a confining two-dimensional quadrupole field to guide the atoms between the two chambers while longitudinally the cloud is allowed to freely expand during the transfer. Strategically placed coils are used to control the longitudinal size and speed of the atomic cloud as it is loaded on the atom chip.We demonstrate efficient loading of neutral atoms into a magnetic waveguide produced by the magnetic fields of microfabricated current-carrying conductors. The lithographically patterned conductors on this ``atom chip'' can be used to make a variety of guiding and trapping structures for manipulating cold atoms and Bose-Einstein condensates. A three-chamber vacuum apparatus collects atoms in a magneto-optical trap, precools them via evaporative cooling, and delivers them to the final chamber containing the atom chip. We describe in detail how the precooled atomic cloud is transferred from a macroscopic magnetic Ioffe-Pritchard trap to the microscopic magnetic waveguide on the atom chip $21\phantom{\rule{0.3em}{0ex}}\mathrm{cm}$ away. Permanent magnets provide a confining two-dimensional quadrupole field to guide the atoms between the two chambers while longitudinally the cloud is allowed to freely expand during the transfer. Strategically placed coils are used to control the longitudinal size and speed of the atomic cloud as it is loaded on the atom chip.

Physical Review AAug 18, 200513 citations

Microscopic magnetic traps for neutral atoms

Jonathan D. Weinstein, Kenneth G. Libbrecht

We describe planar and mostly planar current geometries for constructing microscopic magnetic traps for neutral atoms. These geometries are well-suited for fabrication from superconductors using standard microfabrication techniques. Magnetic-field gradients greater than 5\ifmmode\times\else\texttimes\fi{} ${10}^{5}$ G/cm, and field curvatures greater than ${10}^{8}$ G/ ${\mathrm{cm}}^{2}$ can be produced in microscopic traps. Trap loading could be accomplished by constructing a nested series of traps, and compressing atom clouds from larger traps into smaller ones. In the smallest magnetic microtraps the motional ground-state energy of atoms in the trap can exceed the recoil energy from resonant photons, which may allow direct laser cooling to the trap ground state. If a number of atoms can be simultaneously cooled to the ground state, the resulting ``Bose clusters'' should exhibit interesting optical behavior, since their spatial extent would be less than the resonant light wavelength.We describe planar and mostly planar current geometries for constructing microscopic magnetic traps for neutral atoms. These geometries are well-suited for fabrication from superconductors using standard microfabrication techniques. Magnetic-field gradients greater than 5\ifmmode\times\else\texttimes\fi{}${10}^{5}$ G/cm, and field curvatures greater than ${10}^{8}$ G/${\mathrm{cm}}^{2}$ can be produced in microscopic traps. Trap loading could be accomplished by constructing a nested series of traps, and compressing atom clouds from larger traps into smaller ones. In the smallest magnetic microtraps the motional ground-state energy of atoms in the trap can exceed the recoil energy from resonant photons, which may allow direct laser cooling to the trap ground state. If a number of atoms can be simultaneously cooled to the ground state, the resulting ``Bose clusters'' should exhibit interesting optical behavior, since their spatial extent would be less than the resonant light wavelength.

Physical Review ANov 1, 1995164 citations

Magnetic Microtraps for Cavity QED, Bose-Einstein Condensates, and Atom Optics

Benjamin Lev

The system comprised of an atom strongly coupled to photons, known as cavity quantum electrodynamics (QED), provides a rich experimental setting for quantum information processing, both in the implementation of quantum logic gates and in the development of quantum networks. Moreover, studies of cavity QED will help elucidate the dynamics of continuously observed open quantum systems with quantum-limited feedback. To achieve these goals in cavity QED, a neutral atom must be tightly confined inside a high-finesse cavity with small mode volume for long periods of time. Microfabricated wires on a substrate---known as an atom chip---can create a sufficiently high-curvature magnetic potential to trap atoms in the Lamb-Dicke regime. We have recently integrated an optical fiber Fabry-Perot cavity with such a device. The microwires allow the on-chip collection and laser cooling of neutral atoms, and allow the magnetic waveguiding of these atoms to an Ioffe trap inside the cavity mode. Magnetically trapped intracavity atoms have been detected with this cavity QED system. A similar experiment employing microdisks and photonic bandgap cavities is nearing completion. With these more exotic cavities, a robust and scalable atom-cavity chip system will deeply probe the strong coupling regime of cavity QED with magnetically trapped atoms. Atom chips have found great success in producing and manipulating Bose-Einstein condensates and in creating novel atom optical elements. An on-chip BEC has been attained in a miniaturized system incorporating an atom chip designed for atom interferometry and for studies of Josephson effects of a BEC in a double-well potential. Using similar microfabrication techniques, we created and demonstrated a specular magnetic atom mirror formed from a standard computer hard drive. This device, in conjunction with micron-sized charged circular pads, can produce a 1-D ring trap which may prove useful for studying Tonks gases in a ring geometry and for creating devices such as a SQUID-like system for neutral atoms. This thesis describes the fabrication and employment of these atoms chips in experiments at both Caltech and Munich, the latter in collaboration with Professors Theodore Haensch and Jakob Reichel at the Max Planck Institute for Quantum Optics.The system comprised of an atom strongly coupled to photons, known as cavity quantum electrodynamics (QED), provides a rich experimental setting for quantum information processing, both in the implementation of quantum logic gates and in the development of quantum networks. Moreover, studies of cavity QED will help elucidate the dynamics of continuously observed open quantum systems with quantum-limited feedback. To achieve these goals in cavity QED, a neutral atom must be tightly confined inside a high-finesse cavity with small mode volume for long periods of time. Microfabricated wires on a substrate---known as an atom chip---can create a sufficiently high-curvature magnetic potential to trap atoms in the Lamb-Dicke regime. We have recently integrated an optical fiber Fabry-Perot cavity with such a device. The microwires allow the on-chip collection and laser cooling of neutral atoms, and allow the magnetic waveguiding of these atoms to an Ioffe trap inside the cavity mode. Magnetically trapped intracavity atoms have been detected with this cavity QED system. A similar experiment employing microdisks and photonic bandgap cavities is nearing completion. With these more exotic cavities, a robust and scalable atom-cavity chip system will deeply probe the strong coupling regime of cavity QED with magnetically trapped atoms. Atom chips have found great success in producing and manipulating Bose-Einstein condensates and in creating novel atom optical elements. An on-chip BEC has been attained in a miniaturized system incorporating an atom chip designed for atom interferometry and for studies of Josephson effects of a BEC in a double-well potential. Using similar microfabrication techniques, we created and demonstrated a specular magnetic atom mirror formed from a standard computer hard drive. This device, in conjunction with micron-sized charged circular pads, can produce a 1-D ring trap which may prove useful for studying Tonks gases in a ring geometry and for creating devices such as a SQUID-like system for neutral atoms. This thesis describes the fabrication and employment of these atoms chips in experiments at both Caltech and Munich, the latter in collaboration with Professors Theodore Haensch and Jakob Reichel at the Max Planck Institute for Quantum Optics.

Sep 22, 20056 citations

Micro traps for quantum information processing and precision force sensing

G. Birkl, József Fortágh

Abstract We review recent experimental progress towards quantum information processing and precision force sensing using neutral atoms in micro traps. Microscopic potential structures as generated by optical or electronic microstructures (micro traps) allow for a versatile manipulation of quantum states of atoms and of ultracold atomic quantum gases. Most recent experimental results include the implementation of single‐qubit‐operations in both, optical and magnetic micro traps, as well as in the demonstration of matter‐wave interferometer using Bose‐Einstein condensates coherently split in micro traps.Abstract We review recent experimental progress towards quantum information processing and precision force sensing using neutral atoms in micro traps. Microscopic potential structures as generated by optical or electronic microstructures (micro traps) allow for a versatile manipulation of quantum states of atoms and of ultracold atomic quantum gases. Most recent experimental results include the implementation of single‐qubit‐operations in both, optical and magnetic micro traps, as well as in the demonstration of matter‐wave interferometer using Bose‐Einstein condensates coherently split in micro traps.

Laser & Photonics ReviewDec 12, 200633 citations

21\phantom{\rule{0.3em}{0ex}}\mathrm{cm}

away. Permanent magnets provide a confining two-dimensional quadrupole field to guide the atoms between the two chambers while longitudinally the cloud is allowed to freely expand during the transfer. Strategically placed coils are used to control the longitudinal size and speed of the atomic cloud as it is loaded on the atom chip.

{10}^{5}

G/cm, and field curvatures greater than

{10}^{8}

{\mathrm{cm}}^{2}

can be produced in microscopic traps. Trap loading could be accomplished by constructing a nested series of traps, and compressing atom clouds from larger traps into smaller ones. In the smallest magnetic microtraps the motional ground-state energy of atoms in the trap can exceed the recoil energy from resonant photons, which may allow direct laser cooling to the trap ground state. If a number of atoms can be simultaneously cooled to the ground state, the resulting ``Bose clusters'' should exhibit interesting optical behavior, since their spatial extent would be less than the resonant light wavelength.