Population Loss in Closed Optical Transitions οf Rb and Cs Atoms Confined in Micrometric Thin Cells

Abstract

We present the first experimental observation of narrow dips in the fluorescence profiles of completely closed hyperfine transitions in Rb vapor at high atomic density, which is attributed to the depolarization of the excited state. Moreover, at low atomic density, a narrow peak on the top of the fluorescence profile is demonstrated, centered at the completely closed transition within the D2 line of Cs. Experiments are performed in thin (700 µm) alkali cell by single light beam spectroscopy. The cell is filled with Cs containing a small portion of Rb.

Coherent Population Trapping Resonances in Cs Atomic Vapor Layers of Micrometric Thickness

“…The presence of this bright structure shows that the excited state depolarization does not take place under these conditions. This very interesting narrow pick is rarely observed [12,13]. It is due to the fact that the F g = 4 → F e = 5 transition is completely closed.…”

Saturated absorption spectrum of cesium micrometric-thin cell with suppressed crossover spectral lines

“…This is because the Doppler broadening of alkali atoms at room temperature is typically in range of 400-1000 MHz, [1] which exceeds the separation of adjacent Zeeman sub-levels under strong magnetic field near the hundred-G scale. MCs can realize sub-Doppler-width atomic spectra by saturated absorption spectroscopy, [20] fluorescence spectroscopy, [21] narrow-bandwidth EIT resonance, [22] etc. Among them, saturated absorption spectroscopy is easy to operate and convenient for applications.…”