Magnetic Switch for Integrated Atom Optics

A magnetic waveguide structure allows switching of neutral atoms between two guides. The switch consists of lithographically patterned current-carrying wires on a sapphire substrate. By selectively sending current through a particular set of wires, we select the desired output port of an incoming beam. We utilize two different magnetic-guiding schemes to adiabatically manipulate the atom trajectory

A waveguide atom beamsplitter for laser-cooled neutral atoms

A laser-cooled neutral-atom beam from a low-velocity intense source is split into two beams while guided by a magnetic-field potential. We generate our multimode-beamsplitter potential with two current-carrying wires on a glass substrate combined with an external transverse bias field. The atoms bend around several curves over a $10$-cm distance. A maximum integrated flux of $1.5\cdot10^{5} \mathrm{atoms/s}$ is achieved with a current density of $5\cdot10^{4} \mathrm{Ampere/cm^{2}}$ in the 100-$\mathrm{\mu m}$ diameter wires. The initial beam can be split into two beams with a 50/50 splitting ratio

Guiding neutral atoms around curves with lithographically patterned current-carrying wires

Laser-cooled neutral atoms from a low-velocity atomic source are guided via a magnetic field generated between two parallel wires on a glass substrate. The atoms bend around three curves, each with a 15-cm radius of curvature, while traveling along a 10-cm-long track. A maximum flux of 2*10^6 atoms/sec is achieved with a current density of 3*10^4 A/cm^2 in the 100x100-micrometer-cross-section wires. The kinetic energy of the guided atoms in one transverse dimension is measured to be 42 microKelvin.Comment: 9 page

High-Performance Silicon Photonic Single-Sideband Modulators for Cold Atom Interferometry

The most complicated and challenging system within a light-pulse atom interferometer (LPAI) is the laser system, which controls the frequencies and intensities of multiple laser beams over time to configure quantum gravity and inertial sensors. The main function of an LPAI laser system is to perform cold-atom generation and state-selective detection and to generate coherent two-photon process for the light-pulse sequence. Substantial miniaturization and ruggedization of the laser system can be achieved by bringing together most key functions of the laser and optical system onto a photonic integrated circuit (PIC). Here we demonstrate a high-performance silicon photonic carrier-suppressed single-sideband (CS-SSB) modulator PIC with dual-parallel Mach-Zehnder modulators (DP-MZMs) operating near 1560 nm, which can dynamically shift the frequency of the light for the desired function within the LPAI. Independent RF control of channels in SSB modulator enables the extensive study of imbalances in both the optical and RF phases and amplitudes to simultaneously reach 30 dB carrier suppression and unprecedented 47.8 dB sideband suppression with peak conversion efficiency of -6.846 dB (20.7 %). Using a silicon photonic SSB modulator with time-multiplexed frequency shifting in an LPAI laser system, we demonstrate cold-atom generation, state-selective detection, and the realization of atom interferometer fringes to estimate gravitational acceleration, $g \approx 9.77 \pm 0.01 \,\rm{m/s^2}$, in a Rubidium ($^{87}$Rb) atom system.Comment: 18 pages, 9 figure

Quantitative wave-particle duality and non-erasing quantum erasure

The notion of wave-particle duality may be quantified by the inequality V^2+K^2 <=1, relating interference fringe visibility V and path knowledge K. With a single-photon interferometer in which polarization is used to label the paths, we have investigated the relation for various situations, including pure, mixed, and partially-mixed input states. A quantum eraser scheme has been realized that recovers interference fringes even when no which-way information is available to erase.Comment: 6 pages, 4 figures. To appear in Phys. Rev.

A Compact Cold-Atom Interferometer with a High Data-Rate Grating Magneto-Optical Trap and a Photonic-Integrated-Circuit-Compatible Laser System

The extreme miniaturization of a cold-atom interferometer accelerometer requires the development of novel technologies and architectures for the interferometer subsystems. Here we describe several component technologies and a laser system architecture to enable a path to such miniaturization. We developed a custom, compact titanium vacuum package containing a microfabricated grating chip for a tetrahedral grating magneto-optical trap (GMOT) using a single cooling beam. In addition, we designed a multi-channel photonic-integrated-circuit-compatible laser system implemented with a single seed laser and single sideband modulators in a time-multiplexed manner, reducing the number of optical channels connected to the sensor head. In a compact sensor head containing the vacuum package, sub-Doppler cooling in the GMOT produces 15 uK temperatures, and the GMOT can operate at a 20 Hz data rate. We validated the atomic coherence with Ramsey interferometry using microwave spectroscopy, then demonstrated a light-pulse atom interferometer in a gravimeter configuration for a 10 Hz measurement data rate and T = 0 - 4.5 ms interrogation time, resulting in $\Delta$ g / g = 2.0e-6. This work represents a significant step towards deployable cold-atom inertial sensors under large amplitude motional dynamics.Comment: 21 pages, 10 figure