Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

The average optical reflectivity of bismuth as a function of time t after irradiation by a short laser pulse has been calculated. The amplitude A of photoinduced oscillations in the average optical reflectivity is shown to have extrema under certain conditions. The time τ_j (j is a natural number) at which the amplitude A reaches the jth extremum has been calculated. The calculated dependences of the times τ₁ and τ₂ at which, respectively, the first and second extrema (the first minimum and the first maximum) of the amplitude A are reached on the maximum laser pulse energy density Q are consistent with the experimental data from 8].