Vacuum birefringence detection in all-optical scenarios

Abstract

In this paper we propose an all-optical vacuum birefringence experiment and evaluate its feasibility for various scenarios. Many petawatt-class lasers became operational and many more are expected to enter operation in the near future, therefore unprecedented electromagnetic fields ($E_L\sim10^{14}-10^{15}$ V/m and intensities $I_L\sim10^{21}-10^{23}$ W/cm$^2$) will become available for experiments. In our proposal a petawatt-class laser disturbs the quantum vacuum and creates a delay in a counter-propagating probe laser beam. Placing this delayed beam in one arm of a Mach-Zehnder interferometer (MZI), allows the measurement of the vacuum refraction coefficient via a phase shift. Coherent as well as squeezed light are both considered and the minimum phase sensitivity evaluated. We show that using existing technology and with some moderately optimistic assumptions, at least part of the discussed scenarios are feasible for a vacuum birefringence detection experiment.