Magnetoelectric Jones spectroscopy of alkali atoms

Abstract

The Jones effect in a medium of free atoms exposed to static electric and magnetic fields is a useful tool for determining details of an atomic structure. For atoms in their nS ground states irradiated by a monochromatic wave in resonance with a single-photon transition to an n D state, the bilinear Jones effect is not shaded by the quadratic Kerr and Cotton-Mouton effects, nor by the linear in magnetic field Faraday effect. The position and shape of the amplitude resonance may provide information on spectroscopic properties of atomic levels. We generalize equations for the Jones-effect amplitude to the case of a doublet structure of energy levels and calculate corresponding parameters for alkali atoms. General equations are derived for the amplitude dependence on the relative orientation of the static electric and magnetic fields and on the angle between the static field and the major axis of the wave polarization vector. These equations demonstrate explicitly that the three bilinear-in-static-fields optical birefringence effects-(i) the Jones birefringence (in parallel fields), (ii) the linear birefringence and (iii) the directional birefringence (the last two in perpendicular fields)-correspond to particular cases of the bilinear-in-static-fields correction to the amplitude of Rayleigh forward scattering.

Observation of magneto-electric non-reciprocity in molecular nitrogen gas

“…To our knowledge, up to now this effect has always been observed as a nonreciprocal dichroism [14][15][16], which is related to birefringence through Kramers-Kronig relations. Calculations have been made for atomic gases of alcaline-earth-like atoms near S-P or S-D resonances [10] and alcaline atoms near S-D resonances [11]. All these results are consistent with the expectation that for symmetry reasons, magnetoelectric non-reciprocity (MENR) should have the same order of magnitude as magneto-electric Jones birefringence (MEJB), a birefringence with its eigenaxis oriented at ±45 • with respect to the applied fields.…”

“…In recent years, magneto-electric Jones dichroism has been observed in two atomic parity violation experiments [4,5], where it may generate systematics. Some calculations performed in atomic gases such as alkaline [11] and alkaline-earth-like atoms [10] have confirmed that bilinear magneto-electro-optical effects are far from negligible near some of the atomic resonances. Static electric and magnetic fields may thus become a novel tool for a fine control of the optical properties of the atomic media used in high precision measurements and metrology.…”

Towards a first observation of magneto-electric directional anisotropy and linear birefringence in gases

“…Since our rods provide crossed fields rather than parallel ones as required for Jones birefringence, we will measure the magneto-electric directional anisotropy in Nitrogen, and we therefore expect a slightly different value, probably a few times higher as far as we can infer from various calculations [15][16][17][18]. Comparison with the present 200 µHz sensitivity of our apparatus makes us confident that we should achieve soon the first observation of magneto-electric directional anisotropy in a gas.…”

Towards a first observation of magneto-electric directional anisotropy and linear birefringence in gasesThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

“…Finally, our rods can provide fields B eff = 0.85 T and E = 0.35 MV/m rms on a total length 4L E×B = L 2 = 0.8 m. In such fields, the order of magnitude of the expected frequency modulation due to Jones birefringence in Nitrogen (see Table 1 Since our rods provide crossed fields rather than parallel ones as required for Jones birefringence, we will measure the magneto-electric directional anisotropy in Nitrogen, and we therefore expect a slightly different value, probably a few times higher as far as we can infer from various calculations [15][16][17][18]. Comparison with the present 200 µHz sensitivity of our apparatus makes us confident that we should achieve soon the first observation of magneto-electric directional anisotropy in a gas.…”

“…There is not much literature on magneto-electric effects in gases. Jones birefringence has been computed in usual simple gases [14] for non-resonant light, while analytical calculations are available for alcaline-earth atoms [15] and for alcaline atoms [16] in the vicinity of several atomic resonances. It is worth noting that for all the resonances studied, directional anisotropy is slightly larger than linear birefringence.…”