Intense THz radiation by laser illuminated solid targets

Summary form only given. THz radiation has wide applications in physics, chemistry, information, security and biology. Applications and studies in the nonlinear regime require strong THz radiation sources. Here, we demonstrate intense half cycle THz radiations produced by ultrashort laser solid targets interactions in both forward and backward direction via particle-in-cell simulations. Radiations with intensity higher than 10¹⁴W/cm² near the target surface with the duration approximates that of the incident laser can be obtained by hundreds of TW lasers. Simulations suggest that the radiations are transition radiation¹ induced by hot electrons generated in laser plasma interactions crossing the front and back surface of the target. An overall picture of intense THz generation by laser solid interactions will be presented. Our simulations results are highly consistent with observations from related experiments by other authors^{2, 3}.