Dispersive detection of radio-frequency-dressed states

Abstract

We introduce a method to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection to measure 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.

Floquet description of optically pumped magnetometers

“…) represent the photon flux of elliptical and at 45 • polarized light expressed in terms of creation and annihilation operatorsâ ± andâ † ± for circular polarization components; G (k) F is the rank-k coupling strength and n F are the atoms with the same F -manifold state [27].…”

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

“…An important motivation is the generation of ring and hollow-torus shaped traps 18 and lattices 19 where state-dependent control and simultaneous operation of oppositely oriented Sagnac interferometers is achieved simply via RF-phase changes. Additional aspects include the possibility of low-noise dispersive detection, 20 and also a complex spectrum of hyperfine multi-photon transitions that combine RF-photons from the dressing fields with additional microwave driving. 21 The principle of RF-dressed potentials 22 is to combine static B DC with time-dependent B RF (t) magnetic fields that drive atomic spin-flips.…”

Microwave spectroscopy of radio-frequency-dressedRb87

“…Using free-falling ensembles of 87 Rb atoms released from a magneto-optical trap (MOT) allows us to apply nearly homogeneous magnetic fields to otherwise unaffected atoms. By preparing pure dressed states and using a dispersive detection method to obtain state-dependent signals [32] we are able to attribute spectroscopic features to individual transitions. The state preparation sequence, shown in Fig.…”