Photoluminescence and Terahertz Emission from Femtosecond Laser-Induced   Plasma Channels
  Luminescence as a mechanism for terahertz emission from femtosecond laser-induced plasmas is studied. By using a fully microscopic theory, Coulomb scattering between electrons and ions is shown to lead to luminescence even for a spatially homogeneous plasma. The spectral features introduced by the rod geometry of laser-induced plasma channels in air are discussed on the basis of a generalized mode-function analysis. 
W. Hoyer, J.V. Moloney, E.M. Wright, A. Knorr, M. Kira, and S.W. Koch