Memorized polarization-dependent light scattering in rare-earth-ion-doped glass

We report the observation of memorized polarization-dependent light scatter ing in a Eu2+-doped fluoroaluminate glass sample. Anisotropic light scatter ing along the plane of the light polarization was observed in the glass sam ple after the excitation of a focused 800 nm, 150 fs laser beam at a repeti tion rate of 200 kHz. When we changed the direction of the light polarizati on and irradiated the same location, we observed an anisotropic light-scatt ering pattern identical to the original one at the beginning, but then obse rved a new pattern along the new direction of the light polarization while the original light-scattering pattern disappeared gradually with the passag e of time. This observed phenomenon was considered to be due to the light s cattering of the polarization-dependent permanent microstructure induced by the polarized ultrashort pulsed laser itself. (C) 2000 American Institute of Physics. [S0003-6951(00)01139-6].