Birefringence of interferential mirrors at normal incidence

Abstract

In this paper we present a review of the existing data on interferential mirror birefringence. We also report new measurements of two sets of mirrors that confirm that mirror phase retardation per reflection decreases when mirror reflectivity increases. We finally developed a computational code to calculate the expected phase retardation per reflection as a function of the total number of layers constituting the mirror. Different cases have been studied and we have compared computational results with the trend of the experimental data. Our study indicates that the origin of the mirror intrinsic birefringence can be ascribed to the reflecting layers close to the substrate.

Magnetic linear birefringence measurements using pulsed fields

“…The deduced phase retardation for our mirrors is δ M = (7 ± 6) × 10 −7 rad. Although the origin of the mirrors' static birefringence is still unknown, a review of existing data shows that for interferential mirrors phase retardation per reflection decreases when reflectivity increases [26]. This observation is confirmed by our new measurement.…”

“…The experimental procedure is presented in Ref. [26]. The deduced phase retardation for our mirrors is δ M = (7 ± 6) × 10 −7 rad.…”

Vacuum magnetic linear birefringence using pulsed fields: status of the BMV experiment

“…(14). To check that this corresponds to a meaningful value, we plot the histogram of the following signal for t Γ < t < 0 :…”

“…This static ellipticity is due to the mirrors' intrinsic phase retardation [14]. Each mirror can be regarded as a wave plate.…”

The OVAL experiment: a new experiment to measure vacuum magnetic birefringence using high repetition pulsed magnets

“…Another low pass effect is related to the residual birefringence in the cavity Γ . Each time the light is reflected on the mirror surface, it acquires ellipticity since the surface is not perfectly isotropic [24]. Though the polarization change per reflection is quite small and usually negligible, the ultra-high finesse cavity accumulates the effect and thus significantly affects the small ellipticity measurement.…”