Experimental measurements of optical constants of the metals in the two-temperature state

Complex permittivity of the metals being in the two-temperature state of the electron and the ion sub-systems excited by the femtosecond laser pulses is measured. Diagnostics of the optical properties was performed in the sub-picosecond range, in the visible spectral range at the wavelengths of $800$, $620$, and $400$ nm for gold, silver, nickel, and vanadium under the electron sub-system heating up to $10$–$30$ kK.