Air breakdown threshold and maximum transmitted energy density of 110 GHz terahertz waves

With the development of the power capacity of 110 GHz high-power terahertz waves, the air breakdown by 110 GHz high-power terahertz waves has drawn more and more attention. Several approximations of effective ionization parameters are introduced into the equation of the electron avalanche density, and the breakdown thresholds are calculated at different pressures. The results show that the breakdown thresholds from Ali effective ionization parameters agree very well with the experimental result. The dependence of transmitted energy density on the electric amplitude is also investigated using Ali effective ionization parameters. The results show that, the transmitted energy density increases with the power density linearly when the amplitude is lower than the breakdown threshold; but the transmitted energy density first increases with the amplitude and then decreases when the amplitude is larger than the breakdown threshold.