Effects of optical pulse shape on THz wave generation in laser induced gas plasma

Abstract

Effects of the optical pulse shape on THz wave generation from laser induced plasma was investigated using optical pulse shaping technique. Laser induced plasma is particularly suitable media for THz pulse shaping because of a large freedom of controllable Fourier components over 10 THz. Narrow band THz wave generation was demonstrated using a square wave phase pattern added to optical pulses for a wide tuning range from 2.5–7.5 THz. A combination of pulse shaping technique and adaptive control technique was used to optimize the terahertz wave generation from gas plasma, and 20–25% of power enhancement was achieved. Finally, two pulse sequences were used to generate THz wave form gas plasma, and the effect of the pre-excitation of gas molecule was investigated.