High-intensity THz pulse generation by TW laser radiation in ionized gas and nonlinear crystals

Intense electromagnetic fields can be obtained now in THz frequency range. THz pulses with electric field intensity above 1 MV/cm are now requested for strong-field applications like particle acceleration, short electron bunches measurements, controlling the state of the matter. The advantage of a THz pulse in comparison with the visible frequency range is the almost non-oscillating field that interacts with charged particles more efficiently. The advantage over a direct field is the ability to remotely focus this radiation in space and in time. Except for the huge free-electron lasers facilities, the only way to get THz pulses of MV/cm intensity is the conversion of high-power femtosecond laser pulses. We compare two ways of generating intense THz pulses using the radiation of TW and GW laser systems operating at 800 nm. They are two-color filamentation in gas and optical rectification in nonlinear crystals. The prospects for scaling of THz generation methods for a petawatt laser are discussed.