ABSTRACT
Two sodium phosphate glasses with different structure (meta- and orthophosphate ones) were thermally poled well below the glass transition temperatures. Glass with an orthophosphate structure (glass LA30) demonstrated a typical behavior of polarization current, that is, monotonic current decrease; however, in glass with a metaphosphate structure (glass LA10) the current first increased for 15-20 min and only then started monotonic decreasing. In spite of the similar sodium content, the current in LA10 glass exceeded the one in LA30 glass by about 10 times. This is explained by the capability of substituting intrinsic sodium ions by more mobile protons entering LA10 glass with a metaphosphate structure from the atmosphere. The other difference consists in the fact that the subanodic layer of LA10 glass after poling has many small cracks, while the subanodic layer of LA30 glass is crystallized. It should be emphasized that the crystallization of phosphate glasses under dc electric field below glass transition temperature is observed for the first time. In addition, after poling, no changes in the refractivity of both glasses were detected, but the generation of the second optical harmonic in LA30 glass was observed.
ABSTRACT
A technique for poling of glasses using a resistive barrier discharge plasma in the atmosphere in a gap of hundreds of microns is presented. Measurements of the polarization current, second harmonic generation, and IR spectra of poled soda-lime glass slides show that voltage sufficient to ignite plasma discharge provides efficient poling, whereas for lower voltages the poling effect is close to zero. We attributed this to the large number of hydrogen/hydronium ions generated from atmospheric water vapor by the plasma discharge in the gap, which penetrate into the glass. We also developed a simple model of poling according to Ohm's law, analyzed the temporal dependencies of the polarization current and, basing on the model, estimated mobilities of hydrogen/hydronium and sodium ions in the glass: µH = (2.4 ± 0.8) × 10-18 m2V-1s-1 and µNa = (4.8 ± 1.8) × 10-15 m2V-1s-1. The values obtained are very close to the known literature data.
ABSTRACT
We present a dispersion theory of the surface plasmon polaritons (SPP) in random metal-dielectric nanocomposite (MDN) consisting of bulk metal embedded with dielectric inclusions. We demonstrate that embedding of dielectric nanoparticles in metal results in the formation of the plasmonic bandgap due to strong coupling of the SPP at the metal-vacuum interface and surface plasmons localized at the surface of nanoinclusions. Our results show that MDN can replace metals in various plasmonic devices, which properties can be tuned in a wide spectral range. Being compatible with waveguides and other photonic structures, MDN offers high flexibility in the plasmonic system design.
ABSTRACT
We demonstrate that silver nanoisland film self-assembled on the surface of silver-containing glass in the course of thermal processing in hydrogen is capable to detect 10-7 M concentration of rhodamine 6G in water using surface enhanced Raman spectroscopy (SERS) technique. The film can be multiply restored on the same glass substrate via annealing of the glass in hydrogen. We showed that the film can be self-assembled after as much as ten circles of the substrate cleaning followed by annealing. The proposed technique of the silver nanoisland film formation enables multiple usage of the same glass substrate in SERS experiments.
