Simultaneous measurement of circular dichroism and Faraday rotation at terahertz frequencies using heterodyne detection

Abstract: A far-infrared system measures the full complex Faraday angle, rotation as well as ellipticity, with an unprecedented accuracy of 10\,$\mu$rad/T. The system operates on several far-infrared laser lines in the spectral range from 0.3 to 6 THz and produces results as a continuous function of temperature from 10 to 310K and applied fields between $\pm$ 8\,T. Materials successfully measured include GaAs 2-DEG heterostructures, various high temperature superconductors including Bi$2$Sr$_2$CaCu$_2$O${8+x}$, Pr${2 - x}$Ce${x}$CuO$4$, and La${2-x}$Sr$_x$CuO$_4$, and single crystals of the topological insulator Bi$_2$Se$_3$.