New methods for the production and detection of polarized atoms

Andrey G. Smolin, Oleg S. Vasyutinskii

New expressions for the intensity of two-photon absorption by atomic photofragments are derived for the cases of linearly and circularly polarized light and for all possible spin and orbital states of photofragments. It is shown that these expressions can be used in detailed experimental analysis of products of collisions and photochemical reactions since, in particular, they make it possible to determine explicitly the higher order polarization moments of photofragments.

M. Ya. Agre, Л. П. Рапопорт, M. E. Alferieff

F. K. Lamb, D. ter Haar

Zhibo Cui, Jianyu Pan, Xinyu Tao +8 more

ABSTRACT Atomic magnetometers (AMs) are among the most sensitive magnetic field sensors, with uses in magnetic anomaly detection, geosciences, and fundamental physics research. Despite notable progress, developing highly integrated, miniaturized components with high resolution, sensitivity, and efficiency for chip‐scale AMs remains a significant challenge. Here, we present a novel integrated polarization detection scheme based on a bifocal liquid‐crystal polarization metalens (LCPM) for chip‐scale AMs. By leveraging geometric phase and holographic synthesis principles, the LCPM efficiently separates and focuses left‐ and right‐handed circularly polarized light at the rubidium D1 transition wavelength (795 nm), achieving a high focusing efficiency of up to 80% and extinction ratios of 104 and 134 for the two channels. We demonstrate a prototype AM operating in the spin‐exchange relaxation‐free regime, achieving a high magnetic‐field sensitivity of 17 fT/Hz 1/2 and a dynamic range of ±4.8 nT. The proposed LCPM‐based scheme reduces the optical‐path volume by 94% compared to traditional polarization detection systems. Importantly, our method is compatible with large‐scale, cost‐effective production through established liquid‐crystal manufacturing lines, paving the way for high‐throughput fabrication of chip‐scale AMs. This innovation enables compact, affordable polarization detection with enhanced sensitivity of atomic sensors, opening new opportunities for high‐resolution biomagnetic imaging and quantum precision measurements.

Mahito Kohmoto, U. Fano

A. Robert, O. Sirjean, Antoine Browaeys +5 more

We report the realization of a Bose-Einstein condensate of metastable atoms (helium in the lowest triplet state). The excitation energy of each atom with respect to the ground state is 20 electron volts, but inelastic processes that would destroy the sample are suppressed strongly enough in a spin-polarized sample to allow condensation. Our detection scheme takes advantage of the metastability to achieve detection of individual atoms as well as of the decay products of inelastic processes. This detection opens the way toward new studies in mesoscopic quantum statistical physics, as well as in atomic quantum optics.