The polarization dependence of radiation trapping in the buffer gas environment

In the case of polarized light excitation, the atomic fluorescence which is affected by radiation trapping is partially polarized at the beginning. The time behavior for each polarization component of the fluorescence can be represented by a multiple scattering representation with the natural characteristic time of the sample. Some time after the excitation, the fluorescence is depolarized due to multiple scattering with random direction. In the collision dominant case, the collision makes the depolarization time shorter, which depends on the population transfer between the excited levels. We observed the time behavior of the polarization of fluorescence in an ytterbium-argon mixture and a short depolarization rate. We can interpret the time behavior by using a multiple scattering representation including the population transfer between the excited states due to the collision.