Fraunhofer-type absorption line splitting and polarization in confocal double-pulse laser induced plasma

摘要

Strong line splitting and polarization are observed in Fraunhofer-type absorption lines in Pb, Sn, Si, Cd, In, and Zn in confocal double-pulse laser induced plasma (DP-LIP) experiments. This effect is detectable using medium laser power densities: (-1-2) × 10~(13) W/m~2 for the first laser pulse and 1 × 10~(14) W/m~2 for the second laser pulse. Polarization and splitting effects exist only during the second laser pulse (-7 ns). Absorption line polarization and splitting phenomena may be explained by a high overall magnetic field and motional Stark effect caused by the second laser pulse inside the laser plasma created by the first pulse.