Towards quantum optics experiments with trapped atoms in a hollow-core fibre

A proposal for performing quantum memory schemes with a light matter interface in Hollow Core Fibres is introduced. Various technical aspects of implementing such a scheme in the proposed interface are outlined and the different elements required to realize this scheme are discussed, primarily the detection of atomic levels and the extension of the scheme to magnetically trappable levels. A new method to dispersively measure populations and population difference of alkali atoms prepared in their two clock states is introduced, for future use in the Hollow Core Fibre interface. The method essentially detects the atom numbers based on the influence of the linear birefringence in the ensemble on the detection light beams via polarization homodyning. Sideband detection is performed after dressing the atoms with a radio-frequency field to circumvent low-frequency technical noises. The noise performance of this scheme is discussed along with design modifications aimed at reaching the atomic shot noise limit. Another technical aspect of realizing the quantum memory scheme in the proposed light-matter interface is the extension of the scheme to the trappable states of the atomic system as the atoms will be trapped in an atom chip magnetic field. We achieve this extension by showing the microwave spectroscopy of the ground state ensemble of radio-frequency dressed atoms which proves the existence of pseudo one-photon transitions between the trappable clock states. Finally, the preliminary designs and results of integrating an HCF in an atom chip experiment are discussed

Dispersive detection of radio-frequency-dressed states

We introduce amethod to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection tomeasure populations and population differences of atoms prepared in their clock states. Linear birefringence of the atomic medium enables atom number detection via polarization homodyning, a form of common path interferometry. In order to achieve low technical noise levels, we perform optical sideband detection after adiabatic transformation of bare states into dressed states. The balanced homodyne signal then oscillates independently of field fluctuations at twice the dressing frequency, thus allowing for robust, phase-locked detection that circumvents low-frequency noise. Using probe pulses of two optical frequencies, we can detect both clock states simultaneously and obtain population difference as well as the total atom number. The scheme also allows for difference measurements by direct subtraction of the homodyne signals at the balanced detector, which should technically enable quantum noise limited measurements with prospects for the preparation of spin squeezed states. The method extends to other Zeeman sublevels and can be employed in a range of atomic clock schemes, atom interferometers, and other experiments using dressed atoms

Hafele and Keating on a chip: Sagnac interferometry with a single clock

We describe our progress in the development of an atom based rotation sensor, which employs state-dependent trapping potentials to transport ultracold atoms along a closed path and perform Sagnac interferometry. Whilst guided atom interferometers are sought after to build miniaturized devices that overcome size restrictions fromfree-falling atoms, fully trapped interferometers also remove free-propagation along an atomic waveguide. This provides additional control of motion, e.g. removing wave-packet dispersion and enabling operation that remains independent of external acceleration. Our experimental scheme relies on radio-frequency and microwave-fields,which are partly generated via atom-chip technology, providing a step towards implementing a small, robust, and eventually portable atomic-gyroscope

Towards rotation sensing with a single atomic clock

We discuss a scheme to implement a gyroscopic atom sensor with magnetically trapped ultra-cold atoms. Unlike standard light or matter wave Sagnac interferometers no free wave propagation is used. Interferometer operation is controlled only with static, radio-frequency and microwave magnetic fields, which removes the need for interferometric stability of optical laser beams. Due to the confinement of atoms, the scheme may allow the construction of small scale portable sensors. We discuss the main elements of the scheme and report on recent results and efforts towards its experimental realization

Towards quantum optics experiments with trapped atoms in a hollow-core fibre

A proposal for performing quantum memory schemes with a light matter interface in Hollow Core Fibres is introduced. Various technical aspects of implementing such a scheme in the proposed interface are outlined and the different elements required to realize this scheme are discussed, primarily the detection of atomic levels and the extension of the scheme to magnetically trappable levels. A new method to dispersively measure populations and population difference of alkali atoms prepared in their two clock states is introduced, for future use in the Hollow Core Fibre interface. The method essentially detects the atom numbers based on the influence of the linear birefringence in the ensemble on the detection light beams via polarization homodyning. Sideband detection is performed after dressing the atoms with a radio-frequency field to circumvent low-frequency technical noises. The noise performance of this scheme is discussed along with design modifications aimed at reaching the atomic shot noise limit. Another technical aspect of realizing the quantum memory scheme in the proposed light-matter interface is the extension of the scheme to the trappable states of the atomic system as the atoms will be trapped in an atom chip magnetic field. We achieve this extension by showing the microwave spectroscopy of the ground state ensemble of radio-frequency dressed atoms which proves the existence of pseudo one-photon transitions between the trappable clock states. Finally, the preliminary designs and results of integrating an HCF in an atom chip experiment are discussed

Supplement 2.xlsx

Wavelength-dependent experimental refractive index of tantala (Ta2O5)

Supplementary document for Universal visible emitters in nanoscale integrated photonics - 6446497.pdf

Supporting information. Noise analysis, experimental system details, efficiency modelling and experimental retrieval, polarization measurement description

Three-dimensional, multi-wavelength beam formation with integrated metasurface optics for Sr laser cooling

We demonstrate the formation of a complex, multi-wavelength, three-dimensional laser beam configuration with integrated metasurface optics. Our experiments support the development of a compact Sr optical-lattice clock, which leverages magneto-optical trapping on atomic transitions at 461 nm and 689 nm without bulk free-space optics. We integrate six, mm-scale metasurface optics on a fused-silica substrate and illuminate them with light from optical fibers. The metasurface optics provide full control of beam pointing, divergence, and polarization to create the laser configuration for a magneto-optical trap. We report the efficiency and integration of the three-dimensional visible laser beam configuration, demonstrating the suitability of metasurface optics for atomic laser cooling