Amplification and measurement of sub-degree Faraday rotation based on Fresnel reflection and division-of-focal-plane polarimeters

Faraday rotation measurements in high-energy-density physics (HEDP) experiments using division-of-amplitude methods often suffer from image defects caused by registration errors. To address this, we developed a sub-degree Faraday rotation amplification and measurement system based on division-of-focal-plane polarimeters. Our approach utilizes Fresnel reflections from quartz glass surfaces to enhance polarization rotation, with adjustable magnification controlled by the incident angle. Experimental results demonstrate that this system eliminates registration errors while improving Faraday rotation image quality. The system achieves a high magnification factor k = -29.5 and a measurement standard deviation of 2.6 × 10-2°. The evaluation of plasma self-emission indicates that its impact on the experimental results is negligible, introducing a relative measurement error of less than 0.3%. Its compatibility with Mach-Zehnder interferometers enables direct magnetic field measurements in HEDP experiments.