Observable effects caused by vacuum pair creation in the field of   high-power optical lasers
  We consider the possibility of an experimental proof of vacuum e+e- pair creation in the focus of two counter-propagating optical laser beams with an intensity of the order of 10^20 - 10^22 W/cm^2. Our approach is based on the collisionless kinetic equation for the distribution function of the e+e- pairs with the source term for particle production. As a possible experimental signal of vacuum pair production we consider the refraction of a high-frequency probe laser beam by the produced e+e- plasma to be observed by an interference filter. The generation of higher harmonics of the laser frequency in the self-consistent electric field is also investigated. 
David B. Blaschke, Andrey V. Filatov, Irina A. Egorova, Alexander V.   Prozorkevich, Stanislav A. Smolyansky