THz pulse generation from shaped femtosecond laser pulses interaction with gas-plasma.

Photocurrent and its THz pulse generation from shaped two-color femtosecond laser pulses interaction with gas-plasma are investigated numerically. An opaque filter is used to block some frequency components of the dispersed laser pulse to generate a new shaped pulse. Although the filter decreases the pump laser energy, this method can generate broad, tunable THz pulses. It is found that the width and the position of the filter affect the THz pulse directly because this method generates a different laser pulse shape. In addition, THz generation is also a periodic function of the second harmonic pulse phase.