Femtosecond Fourier interferometry of a nonideal plasma

Experimental diagnostic methods based on the measurement of the reflectance of a plasma are considered. The application of Fourier interferometry for measuring the dynamics of variation of the amplitude and phase of the complex reflectance of the Au plasma for various delay times in intervals shorter than 1 ps relative to the pumping laser pulse with a femtosecond time resolution is described in detail in the intensity range $\sim$10$^{13}$–10$^{14}$ W/cm$^2$. The variation of the complex refractive index of the heated Au target for a pump pulse intensity of $\sim$10$^{12}$–10$^{13}$ W/cm$^2$ is analyzed on the basis of experimental data using the Fresnel formulas.