Structure, nonlinear properties, and photosensitivity of (GeSe_2)_100-x(Sb_2Se_3)_x glasses

Abstract

Chalcogenide glasses from (GeSe 2 ) 100-x (Sb 2 Se 3 ) x system were synthesized, with x varying from 5 to 70, in order to evaluate the influence of antimony selenide addition on nonlinear optical properties and photosensitivity. Nonlinear refractive index and two photon absorption coefficients were measured both at 1064 nm in picosecond regime using the Z-scan technique and at 1.55 µm in femtosecond regime using an original method based on direct analysis of beam profile change while propagating in the chalcogenide glasses. The study of their photosensitivity at 1.55 m revealed highly glass composition dependent behavior and quasi-photostable compositions have been identified in femtosecond regime. To better understand these characteristics, the evolution of the glass transition temperature, density and structure with the chemical composition were determined.

Short range order in Ge-Ga-Se glasses

“…Ge(Ga)-Ge(Ga) bond vibrations in Ge(Ga) 2 Se 6/2 ethane like entities) [13,18,33,34,36,38]. According to our RMC results, we can clearly conclude that this band increasing with Ga content reveals the presence of Ge-Ga bonds in Se-rich Ge-Ga-Se glasses.…”

“…Nevertheless, the Raman spectra of Ge 20 Se 80 , Ge 20 Ga 5 Se 75 and Ge 20 Ga 10 Se 70 glasses are, as expected dominated by two broad bands in the ~175-225 cm -1 and ~230-325 cm -1 spectral regions (see Figure 6). The two peaks observed at ~200 and ~215 cm -1 are attributed to A 1 symmetric stretching mode of corner linked GeSe 4/2 tetrahedra and to A 1 c breathing vibration mode (also called companion mode) likely related to symmetric vibration mode of GeSe 4/2 tetrahedra connected by edge [32][33][34]. The bands related to germanium and gallium structural units certainly overlap due to close atomic weights of these elements and amorphous character of the matrix leading to broad vibration modes [18].…”

Amorphous Ge‐Sb‐Se thin films fabricated by co‐sputtering: Properties and photosensitivity

“…Similar behavior was found in the XPS valence band spectra in bulk Ge‐Sb‐S glasses (Ge 4p , S 3p, and S lp at the VBM). 4 Slight shift in the binding energy might be seen in the XPS valence band spectra when one compares Ge 32 Sb 8 Se 60 and Ge 20 Sb 20 Se 60 glasses . Thus it seems reasonable that the Sb 5p bonding electrons contributing to VBM are responsible for the reduction in bandgap energy in Ge‐Sb‐Se system when increasing antimony content.…”

“…Covalent glasses of ternary Ge‐As‐Se and Ge‐Sb‐Se systems have been recently widely studied due to a large glass‐forming region and good mechanical and physical properties when compared with classical binary chalcogenides. Although the Ge‐As‐Se system is particularly attractive due to its greater glass‐forming region compared to Ge‐Sb‐Se system, the introduction of antimony provides higher polarizability increasing (non)linear refractive index and reduction in photosensitivity, representing an interesting option for nonlinear optics . Last but not least, improved shaping ability of Ge‐Sb‐Se glasses allows fabrication of fibers or thin films, which are of high importance considering optical sensor development, for instance .…”

Surface patterning in Ge Se amorphous layers

“…The structure of the fabricated gratings was investigated via micro-Raman spectroscopy for both as- [28][29][30][31]. These Raman bands show some dependence on the composition in our samples.…”