Linear and nonlinear optical properties of co-sputtered Ge-Sb-Se amorphous thin films
Résumé
Amorphous Ge-Sb-Se thin films were co-sputtered from ${{\rm GeSe}_4}$GeSe and ${{\rm Sb}_2}{{\rm Se}_3}$SbSe targets. Depending on the film composition, linear optical properties were studied by ellipsometry. The Kerr coefficient and two-photon absorption coefficient were estimated using Sheik-Bahae's formalism for co-sputtered films of ${{\rm GeSe}_4} {\text -} {\rm Sb}_2{{\rm Se}_3}$GeSe-SbSe compared to ${{\rm GeSe}_2}{\text -}{\rm Sb}_2{{\rm Se}_3}$GeSe-SbSe pseudo-binary system and ${{\rm As}_2}{{\rm Se}_3}$AsSe as reference. The Kerr coefficient was found within the range of $4.9 {\unicode {x2013}}- 21 \times {10^{ - 18}}$4.9--21×10. Quantitatively by means of a figure of merit at 1.55 µm, thin films with compositions of ${{\rm Ge}_7}{\rm Sb}_{25}{\rm Se}_{68}$GeSbSe and ${{\rm Ge}_9}{\rm Sb}_{20}{\rm Se}_{71}$GeSbSe having an estimated Kerr coefficient of about ${10.1} \times {10^{ - 18}}\;{{\rm m}^2}{{\rm W}^{ - 1}}$10.1×10mW and ${13.4} \times {10^{ - 18}}\;{{\rm m}^2}{{\rm W}^{ - 1}}$13.4×10mW should be considered for the future nonlinear optical integrated platforms. Such compositions being close to ${({{\rm GeSe}_4})_{50}}{({{\rm Sb}_2}{{\rm Se}_3})_{50}}$(GeSe)(SbSe) pseudo-binary (i.e., ${\rm Ge}_{7.5}{\rm Sb}_{25.0}{\rm Se}_{67.5}$GeSbSe) provides just the trade-off between a high Kerr coefficient and low optical losses related to two-photon absorption.
Mots clés
Antimony compounds
Arsenic compounds
Co-sputtered films
Two photon absorption
Selenium compounds
Economic and social effects
Pseudo-binary systems
Non-linear optical
Optical properties
Photons
Amorphous thin films
Thin films
Linear and nonlinear optical properties
Linear optical properties
Integrated platform
Germanium compounds
Nonlinear optics
Kerr electrooptical effect
Optical films
Two photon processes
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