FIR-magneto-spectroscopy is one of the most powerful tools for the experimental investigation of the quantum structure of semiconductors. In fact, the only straight-forward approaches for a direct determination of single-electron band parameters are the standard magneto-transmission and reflection experiments.
O. Portugall, O. Portugall,
"High field magneto-spectroscopy on Hg(Fe)Se", Proc. SPIE 1514, 15th International Conference on Infrared and Millimeter Waves, 151436 (1 December 1990); doi: 10.1117/12.2301524; https://doi.org/10.1117/12.2301524