Self‐assembled organic tubes with linear, bent, crossed and tip‐to‐tip contact geometries show intratube guiding and intertube transfer of input laser light along the tube due to efficient two‐dimensional confinement and one dimensional propagation. The guided light from the tube is exploited to remotely excite a fluorescent meso‐tetratolylporphyrin molecular solid.

Ablation of silver targets immersed in double distilled water (DDW)/acetone was performed with first order, non-diffracting Bessel beams generated by focusing ultrashort Gaussian pulses (~2 and ~40 fs) through an Axicon. The fabricated Ag dispersions were characterized by UV-visible absorption spectroscopy, transmission electron microscopy and the nanostructured Ag targets were characterized by field emission scanning electron microscopy. Ag colloids prepared with ~2 ps laser pulses at various input pulse energies of ~400, ~600, ~800 and ~1000 µJ demonstrated similar localized surface plasmon resonance (LSPR) peaks appearing near 407 nm. Analogous behavior was observed for Ag colloids prepared in acetone and ablated with ~40 fs pulses, wherein the LSPR peak was observed near 412 nm prepared with input energies of ~600, ~800 and ~1000 µJ. Observed parallels in LSPR peaks, average size of NPs, plasmon bandwidths are tentatively explained using cavitation bubble dynamics and simultaneous generation/fragmentation of NPs under the influence of Bessel beam. Fabricated Ag nanostructures in both the cases demonstrated strong enhancement factors (>10 6) in surface enhanced Raman scattering studies of the explosive molecule CL

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(Li0.5K0.5)2x (Sr0.61Ba0.39)1−xNb2O6 (SBN) was prepared by the chemical co-precipitation method. X-ray analysis shows the formation of a single phase tungsten bronze tetragonal structure. Tetragonal unit cell parameters were found to increase with alkali doping up to x = 0.12 along with the tetragonal distortion ratio (c/a). The crystallite size calculated from Scherrer's equation and the grain size determined from SEM micrographs were found to increase with alkali doping up to x = 0.20. Dielectric measurements as a function of temperature show that the Curie temperature shifts towards higher temperature with alkali doping; however, maximum dielectric constant (εmax) and remanent polarization (Pr) were found to increase up to x = 0.12 and then decrease, which is expected to be due to the variation of c/a ratio and density of the sample in the same fashion. Further, the frequency dependent saturation polarization (Pmax) analysis shows a decay of Pmax with frequency, which was expected to be due to the 90° domain contribution at lower frequencies. This decay was found to be well pronounced for SBN, x = 0.12 composition, which suggests the large 90° domain contribution in this composition. This observation is supported by a frequency dependent backswitching study. Fatigue measurement of Pr and Ec carried up to 9 × 105 cycles shows that the samples have best fatigue behaviour up to x = 0.12 composition.

Fe modified Pb0.92La0.08(Zr0.65Ti0.35)O3 (PLZT) was prepared by the conventional method based on the solid state reaction of mixed oxides. The x-ray analysis clearly shows the formation of a PLZT single rhombohedral phase. The crystallite size calculated from Sherrer's equation and the grain size determined from microstructures were found to decrease with Fe doping up to 4%. Calculations carried out for the peak intensity of the x-ray diffraction analysis suggest that Fe occupied the A site up to 4% doping and beyond that it occupied both A and B sites in the ABO3 perovskite structure. Dielectric and pyroelectric measurements show a peak at around the Curie transition temperature. The width of the peaks was found to increase with Fe doping along with decreasing peak dielectric and pyroelectric maxima up to 4%. The P–E loop measurements of PLZT samples with Fe doping up to 6% have shown saturated single loops. Pr and EC from the P–E loop were found to increase with increasing applied field and reached saturation at higher applied fields (25 kV cm−1). However, 8% and 10% Fe doped PLZT have shown double unsaturated hysteresis loops. This anti-ferroelectric phase in Fe doped PLZT samples beyond 8% doping is expected to be due to the occupation of Fe in the B site replacing the Ti atom in the ABO3 perovskite structure.