(Institute for Single Crystals, 2007) Ageev, L.A.; Miloslavsky, V.K.; Makovetsky, E.D.; Beloshenko, K.S.; Stronsky, A.V.
Coloration of fused quartz with colloidal silver (particle radius a ≈ 3 nm) is realized by irradiation of thin (≈ 10 nm) granular Ag film on a quartz plate by a continuous Gauss beam of CO2 laser (λ = 10.6 μm, P = 30 W). Using the AFM microscopy, a relief of the colored surface has been revealed. It is formed by oval lugs with mean transversal size of about ≈ 0.2 μm and heights of several nanometers. The relief is created due to surface deformation caused by subsurface Ag granules. The measured absorption spectrum of the colloid has shown that the absorption band contour is similar to the Lorentz one, maximum being at ω_m = 4.48*10^15 s^(-1), and half-width is γ = 0.714*10^15 s^(-1). Making use of Maxwell-Garnett theory, it has been found that for this colloid, the filling factor is q ≈ 0.05 to 0.10 and coloration depth h ≈ 50 to 100 nm.
