Interaction of colliding laser pulses with gas plasma for broadband coherent terahertz wave generation

This is the authors' abstract. We don't add key points for this paper.

Colliding of two counter-propagating laser pulses is a widely used approach to create a laser field or intensity surge. We experimentally demonstrate broadband coherent terahertz (THz) radiation generation through the interaction of colliding laser pulses with gas plasma. The THz radiation has a dipole-like emission pattern perpendicular to the laser propagation direction with a detected peak electric field 1 order of magnitude higher than that by single pulse excitation. As a proof-of-concept demonstration, it provides a deep insight into the physical picture of laser–plasma interaction, exploits an important option to the promising plasma-based THz source, and may find more applications in THz nonlinear near-field imaging and spectroscopy.