0000000000749628
AUTHOR
L. Skuja
OPTICAL PROPERTIES OF DEFECTS IN SILICA
The optical properties of point defects are frequently the most important parameter in applications of glassy silica. They are relatively easy to measure on standard spectrophotometers and yield direct information on the quality of practical silica-based devices, e.g., attenuation of fiber-optic waveguides or ultraviolet (UV)- transmitting windows. However, optical measurements alone usually do not give enough information to establish the origin and atomic structure of the respective point defects.
Hyper-Rayleigh scattering and two-photon luminescence of phenylamine- indandione chromophores
Based on results of quantum chemical (QC) screening, we put under research several phenylamine indane-1,3-dione derivatives including octupolar NLO chromophore A3BI. According to these calculations, molecular first hyperpolarizability (βHRS) should be enhanced upon replacement of methyl substituents with phenyl groups. Surprisingly, βHRS values obtained in our measurements by hyper-Rayleigh scattering (HRS) are much higher than one could expect from QC. Bearing in mind that two-photon luminescence (TPL) is usual cause for overestimation of βHRS in HRS measurements, we have accomplished investigations of TPL properties of these compounds. All investigated triphenylamine derivatives exhibit s…
Metal doping effects in NIR Raman spectra of YBCO epitaxial films
Metal doping (Co, Zn) of YBCO epitaxial thin films leads to large changes of the scattering efficiencies of various lattice modes in near-infrared (NIR) -Raman spectra (1064 nm) if it is accompanied by a variation of the charge carrier concentration. The results resemble earlier observations in oxygen depleted YBCO thin films. In contrast, no effect is found when metal doping does not change the carrier concentration even if it leads to a massive Tc suppression.