High buffer gas pressure perturbation of coherent population trapping in sodium vapors

Abstract

We report an experimental investigation of coherent population trapping in specially selected Zeeman levels of the sodium atom, performed under high buffer gas pressure in a polydimethylsiloxane coated cell at room temperature. The results show that coherent population trapping will not be completely destroyed when the buffer gas pressure reaches 1100 Torr for He and 1000, 800, and 500 Torr, for Ne, Ar and Kr, respectively. Buffer gases with heavier mass play a larger destructive role for the coherent population trapping. The line width of the dark resonance is reduced with buffer gas pressure. The behavior of the dark resonances on increasing buffer gas is discussed and possible applications are pointed out.