Collapse and revival of a Dicke-type coherent narrowing in potassium vapor confined in a nanometric thin cell

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Vol. 49; no. 7; pp. 75001 - 75007
• Main Authors: Sargsyan, Armen, Pashayan-Leroy, Yevgenya, Leroy, Claude, Sarkisyan, David
• Format: Journal Article
• Language: English
• Published: IOP Publishing 14.04.2016
• Subjects: Dicke narrowing; Doppler effect; Lasers; Mathematical models; nano-cell; Nanostructure; Narrowband; Optical pumping; Potassium; potassium vapor; Resonance absorption
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/0953-4075/49/7/075001

A nanometer-thin cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of . The cell allows one to study the behavior of the resonance absorption over the D1 line of potassium atoms by varying the laser intensity and the cell thickness (from to with the step where is the resonant wavelength of the laser). It is shown that despite the huge Doppler broadening ( at the cell temperature ), at low laser intensities a narrowing of the resonance absorption spectrum is observed for ( at FWHM) and , whereas for and the spectrum broadens. At moderate laser intensities narrowband velocity selective optical pumping (VSOP) resonances appear at and with the linewidth close to the natural one. A comparison with saturated absorption spectra obtained in a 1.4 cm-sized K cell is presented. The developed theoretical model well describes the experiment.