Measuring the stability of polarization orientation in high intensity laser filaments in air

We suggest a method for measuring the polarization orientation of high-intensity beams, by analyzing the damage structures on metal targets, created by laser-plasma-metal interaction. We apply our method on laser filaments and demonstrate stability and instability of the polarization orientation dynamics. Our experimental results show that the polarization orientation of linearly polarized input beams during filamentation is stable, whereas that of elliptically polarized input beams is not. The results are supported by an analytical model.