ABSTRACT
To investigate the laser pulse propagation in an ionizing medium, a three-dimensional (3D) simulation of laser pulse propagation was performed. The refractive index and absorption of neutral atoms, optical Kerr effect, and the change of refractive index with electron density were considered [8]. The spatial and temporal changes of the laser profile during propagation were calculated for the case of a negatively chirped 42-fs laser pulse with 5-mJ energy. The medium was a 9-mm Ne gas jet with a density of 1.4xl018 cm"3. The reason for using a negatively chirped pulse will be discussed later in detail. Truncated Gaussian pulses, which were focused with a power of f/85, were used in the calculation to closely follow actual experimental conditions. The gas jet position is defined as z=0 when the center of the gas jet is positioned at the laser focus.
