Non-linear optical investigations of glass structure

Medium-range ordering in glass structures as a background of photosensitivity in silica fibers

“…1). The introduction of germanium or phosphorous dopant groups into a silica core leads to disappearance of the 570 cm À1 SRS band in silica-based fibers [11].…”

“…The experimental setup used to obtain the SRS spectra in fibers was described elsewhere [11]. The samples of multimode pure silica core fibers, Quartz Co. production, have a step-index profile and plastic cladding.…”

“…In our previous studies, the fundamental spectroscopic aspects of multiple-cascade SRS excitation in silica-based fibers using high-power picosecond pulse laser pumping were formulated and some practical applications of nonlinear SRS spectroscopy in fibers were demonstrated [10][11][12]. It was pointed out that the SRS spectroscopy in fibers is a powerful technique for glass microstructural studies using definite correlations between the anharmonicity constants and the SRS Stokes bandwidths.…”

“…Moreover, in some cases the mixing effect for different Raman-active vibrations leads to the appearance of intense combination bands in the SRS spectra. These bands can be caused by silica tetrahedron vibrations, the vibrations of the so-called ÔdefectÕ groups, and dopant vibrations [11]. Later, the intense SRS Stokes bands originating from photoinduced colour centers capable of effective SHG in silica fibers were observed and interpreted [12].…”

“…Later, the intense SRS Stokes bands originating from photoinduced colour centers capable of effective SHG in silica fibers were observed and interpreted [12]. Some practical applications of SRS spectroscopy in fibers were demonstrated [11].…”