Effects of metal heating on the spectral composition and generation efficiency of terahertz radiation

摘要

Heating of the electrons and lattice of the metal absorbing a femtosecond laser pulse causes a significant increase in the electron collision frequency. This leads to a substantial rise of the generated terahertz radiation field due to more efficient generation by drag force and the electron pressure gradient. Rapid changes in the electron temperature during the pulse are accompanied by the relative amplification of radiation at frequencies greater than the inverse incident pulse duration.