Study of the Magnetically Induced QED Birefringence of the Vacuum in experiment OSQAR

Classical electrodynamics in a vacuum is a linear theory and does not foresee photon-photon scattering or other nonlinear effects between electromagnetic fields. In 1936 Euler, Heisenberg and Weisskopf put framework, in the earliest development of quantum electrodynamics (QED), that vacuum can behave as a birefringent medium in the presence of the external transverse magnetic field. This phenomenon is known as Vacuum Magnetic Birefringence (VMB) and it is still challenging for optical metrology since the first calculations in 1970. When linearly polarized light travels through the strong transverse magnetic field in vacuum, the polarization state of the light would change to elliptical. The difference in the refraction indexes of the ordinary and extraordinary ray is directly related to fundamental constants, such as fine structure constant or Compton wavelength. Contributions to VMB could also arise from the existence of light scalar or pseudoscalar particles, such as axions or axions like particles. Axions couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. This thesis investigates the possibility of the VMB measurement with Large Hadron Collider (LHC) or other superconducting magnets. High sensitive birefringence measurement based on the electro-optic modulator is analytically calculated and experimentally tested on Cotton-Mouton effect (CME) in nitrogen gas. Measurements were made in experiment OSQAR at European Organization for Nuclear Research (CERN). Various sources of noise are discussed, and a sensitivity of the setup is presented. Optical cavities and their implementation are proposed and calculated. At the end of the thesis, the new solution for VMB measurement with superconducting magnets is presented.