Not yet reviewed by Pith; the record is open.

A substantial increase in local laser intensity is observed in the near field behind a plasma shutter.This increase is caused by the interference of the diffracted light at the relativistic plasma aperture and it is studied both analytically and using numerical simulations. This effect is only accessible in the regime of relativistically induced transparency and thus it requires a careful choice of laser and target parameters. The theoretical estimates for the maximum field strength and its spatial location as a function of target and laser parameters are provided and compared with simulation results. Our full 3D Particle-in-Cell simulations indicate that the laser intensity may be increased roughly by an order of magnitude improving the feasibility of strong field QED research with the present generation of lasers.