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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 -cm distance. A maximum integrated flux of
is achieved with a current density of
in the 100- 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, , in a
Rubidium (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 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
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