Sampling of free-space magnetic pulses

Abstract

We report free-space detection of magnetic pulses via the Faraday effect with shot-noise limited detection. This allows a 10−8 T / √Hz magnetic field resolution. The orthogonal propagation of the optical probe beam and the THz waves demonstrate a 1.3 ps risetime with a 400 GHz frequency bandwidth. The temporal and frequency responses of several crystals are reported with a theoretical response function analysis presented. The dispersion of the magnetic pulse into the sensor crystal is illustrated with a theoretical simulation for comparison. We also contrast the properties of electro-optic sampling with this magneto-optic sampling technique.