en عمومى General پژوهشي Research <p style="text-align: justify;">In this paper, the dynamic behavior of laser induced optical breakdown in impure water was studied by using a pump- probe technique. The plasma was induced by a 1064 nm Nd:YAG laser pulse (with pulse duration ~10 ns) in distilled water with two types of impurities: (I) a solution (highly diluted salt water as a conductor) and (II) a colloidal (TiO₂ in colloidal nanoparticle form as a dielectric); and finally the results were compared. The results show that, for both liquids, the probe beam transmission is reduced with pump laser intensity. Our results also show that, impurity size and type of conductivity can influence on plasma time evolution and transmissivity.&nbsp;</p> Highly diluted salt water, Laser induced breakdown, Plasma transmissivity, Pump- probe beam technique, Titanium dioxide nanoparticles. 123 132 http://ijop.ir/browse.php?a_code=A-10-362-2&slc_lang=en&sid=1 Hossein Mozaffari h_mozaffari@physics.iust.ac.ir 10031947532846001967 10031947532846001967 No Iran University of Science and Technology Marzieh Akbari Jafarabadi marziehakbari@iust.ac.ir 10031947532846001968 10031947532846001968 No Iran University of Science and Technology Mohammad Hossein Mahdieh mahdm@iust.ac.ir 10031947532846001969 10031947532846001969 Yes Iran University of Science and Technology