Now you are in the subtree of High-Temperatures Superconductivity project. 


The dispersion of electronic states near the Fermi level can be measured by angle-resolved photoemission. In this technique, one typically shines ultraviolet photons on a flat crystal surface and measures emitted electrons as a function of angle, analyzing the electron current as a function of kinetic energy. Light sources include the He lamp (photon energy 20 eV), synchrotrons (tunable from UV to soft x-ray to hard x-ray), and lasers (6-7 eV). [1]


  1. A. Damascelli, Z.-X. Shen, and Z. Hussain, Rev. Mod. Phys. 75, 473–541 (2003).