Reconstruction of fundamental absorption spectra of material by its refractive index spectrum in transparency region

摘要

The method of calculation of the fundamental absorption index spectrum k(E) of crystalline dielectrics on the basis of refractive index spectrum n(E$-0$/) in the range of transparency by solving the Kramers-Kronig integral equation has been worked out. Limited experimental precision of refractive index measurements, $delta@n/n equals 10$+$MIN@4$/, permits us to obtain low-structuralized (smoothed) k(E) spectra. The method was applied to the ferroelectrical triglycine sulphate crystal. The refractive index dispersion of this crystal reveals the interaction of elementary oscillators. The temperature dependence of characteristic parameter of this interaction was studied in the region including the phase transition (T$-c$/ equals 49 degrees Celsius).