Spectroscopy of atoms in confined media
We spectroscopically investigate Rb atomic vapors confined in alumina nanotubes. In this 2D confinement we observe the diffusive dynamics of the movement of atoms inside the nanotubes. We discovered that it is possible to modify this diffusion process through the action of non-resonant light. Light reduces the residence time of the adsorbed atoms on the internal surface of the nanotubes through an effect called LIAD (Light Induced Atomic Desorption) [Vil10]. Later we developed porous glass spectroscopic cells, where the Rb atoms are housed in the micrometric interstices of the porous medium. These spectroscopic media present the originality that the atoms interact with the light that diffuses through the porous medium [Vil13]. The interaction of confined vapors with diffuse light has unique consequences on spectroscopic signals.
Despite the 3D confinement that atoms experience in these media, and the diffuse nature of light, we observe spectroscopic signals with widths close to natural [Vil14]. We also perform two-photon spectroscopy, for which we observe spectral lines with a very unique and characteristic shape [Amy17].
Within the framework of these investigations, we developed a novel spectroscopic method to characterize a porous medium that allows measuring the characteristic dimension of its pores [Fai19].
[Vil10] “Light-induced atomic desorption and diffusion of Rb from porous alumina», S. Villalba, H. Failache and A. Lezama, Phys. Rev. A 81, 032901 (2010) .
[Vil13] “Rb optical resonance in a random porous medium“, S. Villalba , H. Failache, A. Laliotis, L. Lenci, S. Barreiro, A. Lezama. Optics Letters 38(2), 193-195 (2013).
[Vil14] “Sub-Doppler resonances in the back-scattered light from random porous media infused with Rb vapor“, S. Villalba, A. Laliotis, L. Lenci, D. Bloch, A. Lezama, H. Failache. Phys. Rev. A 89, 023422 (2014).
[Amy17] “Two-photon excitation of rubidium atoms inside porous glass“, L. Amy, L. Lenci, S. Villalba, H. Failache, A. Lezama. Phys. Rev. A 96, 043819 (2017).
[Fai19] “Measurement of the size of voids in dielectric media“. H. Failache, L. Amy, S. Villalba and A. Lezama, Journal of Applied Physics 126, 125103 (2019).
