We report on femtosecond laser modification of Nd:SBN crystals. Basic properties such as the ablation threshold have been obtained from the analysis of the ablation depths at different laser fluences. The induced micromodifications have been investigated by optical microscopy as well as by microphotoluminescence and micro-Raman experiments. We have found that in the vicinity of the ablated volume material amorphization can be induced along different directions. Furthermore, we have found that this material amorphization is accompanied by a strong inhibition of the Nd$^{3+}$ luminescence. The analysis of the spatial extension of the luminescence inhibition as a function of the laser fluence has been used to elucidate the origin of the femtosecond laser induced material amorphization.