Vacuum polarization, an effect originally predicted nearly 70 years ago, is still yet to be directly detected despite significant experimental effort. Previous attempts have made use of large liquid-helium cooled electromagnets which inadvertently generate spurious signals that mask the desired signal. We present an approach for the ultrasensitive detection of optical birefringence that can be usefully applied to a laboratory detection of vacuum polarization. The technique has a predicted birefringence measurement sensitivity of Deltansimilar to10(-20) in a 1 s measurement. When combined with the extreme polarizing fields achievable in this design we predict that a vacuum polarization signal will be seen in a measurement of just a few days in duration.
Luiten, A., & Petersen, J. C. (2004). Ultrafast resonant polarization interferometry: Towards the first direct detection of vacuum polarization. Physical Review A, 70(3), 033801-1-033801-9. https://doi.org/10.1103/PhysRevA.70.033801