Observation of very high order multi-photon absorption in GeSbS chalcogenide glass

Abstract

We report high order multi-photon absorption in Ge23Sb7S70 chalcogenide glasses up to the 11th order. Open aperture z-scan measurements with enhanced detection capabilities are performed at short-wave to mid-infrared wavelengths between 1.1 μm and 5.5 μm, enabling very high order multi-photon absorption to be experimentally observed. We report the multi-photon absorption coefficients for Ge23Sb7S70 within the measurement range corresponding to 3-11 photon absorption. The dispersive Kerr nonlinear index of the chalcogenide glass in the short-wave to mid-infrared wavelength range is measured, resulting in a peak n2 value of 4.4 × 10−18 m2/W. Enhancements to the nonlinear refractive index from the presence of defect states are observed. We further report experimentally verified multi-photon absorption excitation of photoluminescence in Ge23Sb7S70 chalcogenide glasses. The results pave the way for previously unexplored, new paradigms of photonic device design leveraging very high order multi-photon absorption effects and multi-photon excited photoluminescence.