Vacuum Birefringence Measurement via All-Optical Interferometric Schemes

Abstract All-optical vacuum birefringence experiments will get increasingly closer to feasibility as multi-petawatt laser facilities become operational around the World. Thus, the availability of focused laser intensities in the order of I L ∼ 10 22 −10 24 W/cm 2 are to be expected in a focused spot size ∼ 3 − 5 μ m. With these values, vacuum refraction indices in the order of Δ n ∼ 10 −11 − 10 −9 are possible with an induced phase delay on a counterpropagating optical probe beam in the order of Δφ ∼ 10 −9 −10 −7 radians. We discuss two all-optical interferometric schemes and detail the Mach-Zender interferometric proposal. We consider this interferometric scheme fed by both classical and non-classical input light and with two detection schemes. We outline scenarios that are likely to lead to a feasible experimental implementation.