Optical breakdown probability in silicone oil by short pulsed Q-switched lasers

The behavior of the breakdown probability in distilled water was studied so far using short pulse 1.06 mum and 0.532 mum lasers. Results obtained were analyzed by a equation which was used in avalanche breakdown in gases and semiconductors under DC voltage application. This equation can not explain the electron mean free path dependence of the breakdown probability under optical field application and also does not include the optical frequency dependence. A new equation of the breakdown probability under optical field application was proposed taking account of the mechanism of energy gain of the electron in the optical field. Breakdown probability measurements were done in silicone oils with various viscosities (or densities) using 1.06 mum and 0.532 mum lasers to verify the new equation.