Electric-current transients driven by high-peak-power midinfrared laser pulses are shown to provide a source of broadband current, wide-angle microwave-terahertz radiation, whose spectral, spatial, and polarization properties can be adequately understood from a perspective of impulsively driven antenna radiation. When suitably tailored, such laser-driven antennas are shown to generate bright microwave-terahertz pulses with energies in the range of tens of microjoules and ultrawide-angle radiation patterns extending to obtuse angles well beyond the broadside plane, with a considerable radiation flux detected at angles $\theta >{125}^{\circ }$ relative to the direction of the driver beam. Polarization of microwave radiation from laser-driven plasmas is shown to bear clear signatures of the symmetry of transient plasma currents, providing a sensitive probe for ultrafast laser-plasma interactions.

• Received 20 October 2021
• Accepted 23 March 2022

DOI:https://doi.org/10.1103/PhysRevA.105.053503