Diagnostics of Femtosecond Laser-Plasmas Using Fundamental and Second Harmonic Emission

By observing the fundamental and second harmonic emission from a plasma produced by a 150fs, 5mJ laser at 800nm, the electron temperature, the expansion speed and the scalelength of the plasma have been diagnosed. Moreover the polarization of the fundamental and second harmonic emission has been studied. This could be a useful diagnostic for modulation at the critical surface of the plasma.