Tigran Varzhapetyan | Searcharxiv

arXiv2005

Laser spectroscopy with nanometric gas cells : distance dependence of atom-surface interaction and collisions under confinement

The high sensitivity of Laser Spectroscopy has made possible the exploration of atomic resonances in newly designed "nanometric" gas cells, whose local thickness varies from 20nm to more than 1000 nm. Following the initial observation of the optical analogous of the coherent Dicke microwave narrowing, the newest prospects include the exploration of long-range atom surface van der Waals interaction with spatial resolution in an unprecedented range of distances, modification of atom dielectric resonant coupling under the influence of the coupling between the two neighbouring dielectric media, and even the possible modification of interatomic collisions processes under the effect of confinement.

physics.atom-ph↗

arXiv2003

Sub-Doppler spectroscopy of Rb atoms in a sub-micron vapor cell in the presence of a magnetic field

We report the first use of an extremely thin vapor cell (thickness ~ 400 nm) to study the magnetic-field dependence of laser-induced-fluorescence excitation spectra of alkali atoms. This thin cell allows for sub-Doppler resolution without the complexity of atomic beam or laser cooling techniques. This technique is used to study the laser-induced-fluorescence excitation spectra of Rb in a 50 G magnetic field. At this field strength the electronic angular momentum J and nuclear angular momentum I are only partially decoupled. As a result of the mixing of wavefunctions of different hyperfine states, we observe a nonlinear Zeeman effect for each sublevel, a substantial modification of the transition probabilities between different magnetic sublevels, and the appearance of transitions that are strictly forbidden in the absence of the magnetic field. For the case of right- and left- handed circularly polarized laser excitation, the fluorescence spectra differs qualitatively. Well pronounced magnetic field induced circular dichroism is observed. These observations are explained with a standard approach that describes the partial decoupling of I and J states.

physics.atom-ph↗