Polarizers, optical bridges and Sagnac interferometers for nanoradian polarization rotation measurements

Abstract

The ability to measure nanoradian polarization rotations, ${\theta }_F$, in the photon shot noise limit is investigated for partially crossed polarizers (PCP), a static Sagnac interferometer and an optical bridge, each of which can in principal be used in this limit with near equivalent figures-of-merit (FOM). In practice a bridge to PCP/Sagnac source noise rejection ratio of $1/4{\theta }_F^2$ enables the bridge to operate in the photon shot noise limit even at high light intensities. The superior performance of the bridge is illustrated via the measurement of a 3 nrad rotation arising from an axial magnetic field of 0.9 nT applied to a terbium gallium garnet. While the Sagnac is functionally equivalent to the PCP in terms of the FOM, unlike the PCP it is able to discriminate between rotations with different time ($T$) and parity ($P$) symmetries. The Sagnac geometry implemented here is similar to that used elsewhere to detect non-reciprocal ($\overline{T}P$) rotations like those due to the Faraday effect. Using a Jones matrix approach, novel Sagnac geometries uniquely sensitive to non-reciprocal $\overline{TP}$ (e.g. magneto-electric or magneto-chiral) rotations, as well as to reciprocal rotations (e.g. due to linear birefringence, $TP$, or to chirality, $T\overline{P}$) are proposed.

12 pages, 7 figures

References in corpus (6)

• 3D-Chiral Metamaterial Showing Artificial Magnetic Response and Negative Refraction
• Giant Faraday rotation in single- and multilayer graphene
• High Resolution Polar Kerr Effect Measurements of Sr2RuO4: Evidence for Broken Time Reversal Symmetry in the Superconducting State
• Modified Sagnac interferometer for high-sensitivity magneto-optic measurements atcryogenic temperatures
• Constraints on Jones transmission matrices from time-reversal invariance and discrete spatial symmetries
• A Scanning, All-Fiber Sagnac Interferometer for High Resolution Magneto-Optic Measurements at 820 nm

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