Ellipticity Induced in Vacuum Birefringence

Improving ellipticity detection sensitivity for the Q & A vacuum birefringence experiment

Q & A (quantum electrodynamics test and search for axion) experiment was first proposed in 1994 and a 3.5 m high-finesse Fabry-Perot prototype detector extendable to 7 m has been built and tested. We now enter into the 2nd phase of improving the ellipticity detection sensitivity. We present our scheme, compare with other ongoing experiments, analyze the displacement spectra of our suspension sy...

Technical Note: Stress-Induced Birefringence in Vacuum Systems

Even scientific grade optical glasses show birefringence when small external forces are applied to the sample. Stress-induced birefringence can be particularly detrimental to the state of polarization of light when a laser beam is transmitted through the glass. This is especially the case for glass windows of a vacuum chamber. Since compensation of spatially inhomogeneous birefringence is extre...

Vacuum Birefringence as a Vacuum Emission Process

We argue that the phenomenon of vacuum birefringence in strong inhomogeneous electromagnetic fields can be most efficiently analyzed in terms of a vacuum emission process. In this contribution, we exemplarily stick to the case of vacuum birefringence in a stationary perpendicularly directed, purely magnetic background field extending over a finite spatial extent. Similar field configurations ar...

Vacuum Birefringence in a Rotating Magnetic Field

We calculate the vacuum polarization-induced ellipticity acquired by a linearly polarized laser beam of angular frequency ω̄ on traversing a region containing a transverse magnetic field rotating with a small angular velocity Ω around the beam axis. The transmitted beam contains the fundamental frequency ω̄ and weak sidebands of frequency ω̄±2Ω, but no other sidebands. To first order in small quan...

Vacuum birefringence in strong inhomogeneous electromagnetic fields