Coherent terahertz wave emission from laser-induced plasma in isotropic transparent solid dielectrics

In this Letter, we employ fused silica and two types of optical glass as examples to investigate the coherent terahertz(THz)wave emission from laser-ionized isotropic transparent dielectrics. Based on the laser energy and incident angle dependences, we ascribe the THz emission to the ponderomotive force-induced dipole oscillation. Additionally, our investigation on the dependence of THz amplitude on the laser pulse duration confirms the dominant role of avalanche ionization in solid dielectrics. The THz emission can be utilized to indirectly monitor the ultrafast dynamics of carrier generation and motion during the laser ionization process of solid dielectrics.