Jerzy Zachorowski

Nonlinear magneto-optical rotation with frequency-modulated light in the geophysical field range

Recent work investigating resonant nonlinear magneto-opticalrotation (NMOR) related to long-lived (tau_rel approx 1s) ground-stateatomic coherences has demonstrated potential magnetometric sensitivitiesexceeding (10-11 G Hz-1/2) for small (<1 micro G) magnetic fields. Inthe present work, NMOR using frequency-modulated light (FM NMOR) isstudied in the regime where the longitudinal magnetic field is in thegeophysical range (sim 500mG), of particular interest for manyapplications. In this regime a splitting of the FM NMOR resonancedue tothe nonlinear Zeeman effect is observed. At sufficiently high lightintensities, there is also a splitting of the FM NMOR resonances due toac Stark shifts induced by the optical field, as well as evidence ofalignment-to-orientation conversion type processes. The consequences ofthese effects for FM-NMOR-based atomic magnetometry in the geophysicalfield range are considered.

Nonlinear magneto-optical rotation with amplitude modulated light

We study the possibility of creating quantum superposition states in alkali atoms. Our methodology is based on the phenomenon of nonlinear magneto-optical rotation (NMOR). The effect of magneto-optical rotation occurs whenever the resonant light propagates through the medium immersed in a longitudinal magnetic field and manifests itself as a rotation of the polarization plane of light. The effect is strongly enhanced by the nonlinearity of light-atom interaction and allows state-of-the art atomic magnetometry. On the other hand, the nonlinear magneto-rotation provides means to controllably affect and detect atoms quantum state. We present the work on this topic and report on some characteristics of superposition quantum states such as lifetimes or efficiency of its creation in various conditions.

Magnetometry based on nonlinear magneto-optical rotation with amplitude-modulated light

Nonlinear magneto-optical rotation (NMOR), an all-optical technique now finding its use in sensitive magnetometry, is light-intensity-dependent rotation of the polarization plane of linearly polarized light upon its propagation through a medium placed in a magnetic field. NMOR technique enables measurements of magnetic field from 0 to 50 muT with the expected sensitivity of 10-14 T Hz-1/2.

Time-of-flight measurement of the temperature of cold atoms for short trap-probe beam distances

We analyse the time-of-flight method of measuring the temperature of cold trapped atoms in the specific case of short distances of the probe beam from the trap centre and finite atomic cloud size. We theoretically examine the influence of the probe beam shape and its distance from the initial position of the cloud on the temperature evaluation. These results are then verified with a three-dimensional Monte Carlo simulation and applied to our experimental data to show that the proposed procedure allows accurate and reliable determination of the temperature.

Probe spectroscopy in an operating magneto-optical trap: The role of Raman transitions between discrete and continuum atomic states

We report on cw measurements of probe beam absorption and four-wave-mixing spectra in a {sup 85}Rb magneto-optical trap taken while the trap is in operation. The trapping beams are used as pump light. We concentrate on the central feature of the spectra at small pump-probe detuning and attribute its narrow resonant structures to the superposition of Raman transitions between light-shifted sublevels of the ground atomic state and to atomic recoil processes. These two contributions have different dependencies on trap parameters and we show that the former is inhomogeneously broadened. The strong dependence of the spectra on the probe-beam polarization indicates the existence of large optical anisotropy of the cold-atom sample, which is attributed to the recoil effects. We point out that the recoil-induced resonances can be isolated from other contributions, making pump-probe spectroscopy a highly sensitive diagnostic tool for atoms in a working magneto-optical trap.

Absolute measurement of the 1S0 − 3P0 clock transition in neutral 88Sr over the 330 km-long stabilized fibre optic link

We report a stability below 7 × 10−17 of two independent optical lattice clocks operating with bosonic 88Sr isotope. The value (429 228 066 418 008.3(1.9)syst (0.9)stat Hz) of the absolute frequency of the 1S0 – 3P0 transition was measured with an optical frequency comb referenced to the local representation of the UTC by the 330 km-long stabilized fibre optical link. The result was verified by series of measurements on two independent optical lattice clocks and agrees with recommendation of Bureau International des Poids et Mesures.

Strontium optical lattice clocks for practical realization of the metre and secondary representation of the second

We present a system of two independent strontium optical lattice standards probed with a single shared ultranarrow laser. The absolute frequency of the clocks can be verified by the use of Er:fiber optical frequency comb with the GPS-disciplined Rb frequency standard. We report hertz-level spectroscopy of the clock line and measurements of frequency stability of the two strontium optical lattice clocks.

Conical emission in barium vapour

Abstract Studies of the angular structure of a pulsed dye-laser beam transmitted through a dense barium vapour are reported. In contrast to previous experiments, self-trapping of the laser beam has been excluded and precise control over the light intensity within the nonlinear medium was attained. Evidence is provided that the cone of light generated by the laser tuned to the blue side of the atomic resonance stems from the low-frequency Rabi sideband. This resolves the long-lasting ambiguity about the origin of conical emission for blue detuning.

Degenerate parametric emission in dense barium vapour

Abstract Studies of degenerate parametric interaction in laser beam propagation through dense barium vapour are reported. Various transverse instabilities have been observed when two strong, copropagating beams intersect in the medium. Most of them are attributed to parametric interaction of the intersecting beams and their main features are consistent with the existing four-wave mixing formalism. The conditions of their generation and their mutual competition are discussed.

Bound and free atoms diagnosed by the recoil-induced resonances: 1D optical lattice in a working MOT

Rb atoms in a magneto-optical trap MOT and one-dimensional optical lattice. Using Raman pump-probe spectroscopy, we observe the coexistence of two atomicfractions: the first consists of free, unbound atoms trapped in a MOT and the second is localized in themicropotentials of the optical lattice. We show that recoil-induced resonances allow not only temperaturedetermination of the atomic cloud but, together with vibrational resonances, can also be used for real-time,nondestructive studies of the lattice loading and of the dynamics of systems comprising unbound and boundatomic fractions.DOI: 10.1103/PhysRevA.73.063414 PACS number s : 32.80.Pj, 42.50.Vk, 42.65. k