Refractive index dispersion of AgCl1-xBrx (0≤x≤1) and Ag1-xTlxBr1-xIx (0≤x≤0.05)

Abstract For polycrystalline AgCl 1- x Br x (0 ≤ x ≤ 1) and Ag 1- x Tl x Br 1- x I x (0 ≤ x ≤ 0.05) thin plates manufactured by hot embossing, we recorded the ultraviolet (UV) to near-infrared (NIR) transmission spectra in order to reveal the absorption edge and to measure the refractive index at short wavelengths. The former moves towards longer wavelengths and the latter increases significantly, when the substituting agent content in the solid solution ( x ) is being increased. Using mid-infrared (MIR) spectra, recorded by Fourier-transform infrared spectroscopy (FTIR), we determined both real ( n ) and imaginary ( k ) parts of the refractive index at 4.5, 5.0, 8.0, 12.0, 14.0 μm. These data, together with the ones collected earlier with He-Ne laser and at 10.6 μm via FTIR, allow observing that the introduction of a heavy substituting agent into a host lattice forces the refractive index to grow gradually at a fixed wavelength and to fall considerably within each composition (vice versa for the extinction coefficient), especially in the NIR. Fresnel reflection ( R ) and absorption coefficients ( K ) were also calculated, and several error-calculation equations for n, k, K, and R were proposed concerning all contributions of each approach used.