Optical stabilization of Rb vapor density above thermal equilibrium

• Published in: Journal of modern optics Vol. 57; no. 14-15; pp. 1305 - 1310
• Main Authors: Burchianti, A., Bogi, A., Marinelli, C., Mariotti, E., Moi, L.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis Group 10.08.2010; Taylor & Francis; Taylor & Francis Ltd
• Subjects: alkali metals; alkali vapor cells; atomic spectroscopy; Chemical elements; Control systems; Density; Desorption; desorption induced by photon stimulation; Dielectrics; Exact sciences and technology; Fluorescence; Fundamental areas of phenomenology (including applications); Glass; Heat; Illumination; Lasers; Optics; organic films; Physics; porous glass; Semiconductor lasers; laser diodes; Spectrum analysis; Stabilization; Thermodynamics; Semiconductor lasers; Feedback; Dielectric materials; Porous materials; Glass; Fluorescence; Photoinduced effect; Rubidium Atoms; Laser diodes
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500341003605429

We stabilize the Rb vapor density above its thermal equilibrium value in sealed glass cells, which are generally used in atomic physics experiments. The method relies on light-induced desorption of Rb atoms from dielectric surfaces. The process does not demand high light intensities so that LEDs or laser diodes can be used as desorbing sources. The experiments are carried out in Pyrex cells either coated with a polydimethylsiloxane film or containing a porous glass sample. Under illumination both the organic coating and the porous sample release a large amount of Rb atoms into the cell volume. We show that the Rb vapor density can be maintained to a preset value, using a desorbing light intensity controlled by a feedback signal given by the Rb absorption or fluorescence level. Moreover, we find that the stabilization technique does not depend on the microscopic mechanisms underlying photodesorption.