Effect of absorption oscillation of resonant radiation observed in a compact installation for hyper-polarization of 129Xe

This work presents the discovery and study of a new, to the best of our knowledge, effect of oscillation of resonant radiation absorption in optical cells with rubidium vapor in the presence of xenon and nitrogen inside an installation for xenon polarization by spin-exchange optical pumping. This effect was observed at temperatures of 100°C–130°C, partial xenon pressure exceeding 100 kPa, total gas mix pressure of 400 kPa, and power of broad-band (Δ𝜆=∼2nm) laser radiation over 2 W. The highest registered magnitude of power oscillations of the transmitted radiation exceeded 20%, the oscillation period depending on the temperature and lying in the range of 4.8–7 s. The conducted measurements of the parameters of the transmitted radiation lead to the conclusion that the discovered effect is related to concentration oscillations of the atomic rubidium vapor, which probably arises due to cyclic dimerization of rubidium or an oscillating continuous chemical reaction of rubidium and the optical cell contents.