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The vitreous formation in a new chalcohalogenide system based on As, Sb, Bi, S, Pb and I has been studied. Wide vitreous regions have been identified both in the ternary As2S3–Sb2S3–PbI2 system and in the quaternary As2S3–Sb2S3–Bi2S3–PbI2 system. More particularly, in the latter case, the vitreous regions have been investigated and established for the two layers of the system corresponding respectively to 10% and 20% molar of Bi2S3. Due to the richness of these new glasses in highly polarizable elements, they are of interest for the implementation of high nonlinear optical properties. To explore the potentialities of chalcogenide glasses for ultra-fast optical applications, the nonlinear refractive indices (real and imaginary part) of different compositions are measured. Nonlinear measurements have been performed through a pump/probe experiment using a Mach-Zehnder interferometer coupled to a CCD camera. The measured values are as high as 16×10−18 m2/W for the nonlinear refractive index and 6 cm/GW for the nonlinear absorption. [Copyright &y& Elsevier]

Abstract: Determination of the composition with the best optical and physical properties in a sulfide–halide arsenic-free vitreous domain, GeS2–Sb2S3–CsI, is described. The characteristic temperatures: glass transition (T g) and crystallization temperatures (T x) are measured to determine the difference T x−T g. The nonlinear index and absorption, the linear index are measured on nine samples in the vitreous domain. With an experimental device, cartographies of each property are created. The model permits to find a composition with a good compromise for T x−T g, nonlinear index and nonlinear absorption. The model emphasizes the influence of each element on each property. [Copyright &y& Elsevier]

Abstract: The non-linear optical response of sulphide glass-containing β-GeS2 microcrystallites, has been studied at a fundamental wavelength of λ=5.5μm under additional irradiation by IR-pulses of λ=3.7μm. A substantial increase of the non-linear susceptibility with IR-power and size of the microcrystallites has been found. Molecular dynamics calculations linked to quantum chemical calculations show that this effect could be explained by substantial contributions of the microcrystallite interfaces and due to the phonon sub-system. The role of anharmonic electron–phonon effects is experimentally confirmed by the observation of an optimal delay of 8ps between the pump laser pulses at 3.7μm and the probing laser pulses at 5.5μm, which generate the observed second harmonic signal. [Copyright &y& Elsevier]

We show that highly nonlinear two-photon absorption coefficients can be obtained in infrared glasses (tellurium based chalcogenide glasses) at 1.06 μm and in the picosecond range (twice that of As2Se3). We observe an intensity-dependant two-photon absorption coefficient. This dependence is attributed to higher order effects occurring in nonlinear absorption process in our materials. The corresponding nonlinear coefficients are deduced from experimental data using a closed-form relation relating the effective two-photon absorption coefficient to the incident intensity. These coefficients become larger as the photon energy increases relative to the band gap. [Copyright &y& Elsevier]