[en] Interaction of high intensity laser pulse with plasma is becoming popular field of research for designing and developing future particle accelerators in the high energy range. Particle accelerators based on relativistic electron beam / laser pulse injection can be used to create high electric field gradient up to the order of TeV/m which can be very useful in study of high energy physics phenomena and understanding the formation of universe. Present study deals with nonlinear interaction of high intensity laser pulse with plasma which is responsible for generating electrostatic plasma oscillations which in turn generate Wakefield's in the plasma. These high gradient Wakefield's are further used to accelerate injected electrons or any charged particles trapped in the wake. Acceleration and speed gained by such trapped charged particles is directly proportional to the magnitude of wakefield gradient