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A set of new methacrylate monomers based on azobenzene/azomethine moieties coupled with an antipyrine heterocyclic fragment was designed. Their free radical polymerization provided six homo-/copolymers with photoactive side chains. These novel materials were characterized with NMR, IR and UV-vis spectroscopies, as well as DSC and SEC. Their THF solutions demonstrated an efficient refractive nonlinear optical (NLO) response with an optical quality factor, FOM, of 102 – 2 × 103via self-action of single picosecond range laser pulses at a wavelength of 532 nm. Their efficiency enhances in the following set of chromophores: azomethine < azo < bis-azomethine. The polymers exhibit higher cubic hyperpolarizabilities against their corresponding initial molecules, while the fractional contribution of the photoactive group reduces. Incorporation of bis-structured units improves both the polymer properties and the NLO response efficiency of the materials. The fractional contribution of a photochromic group to the macromolecular refractive/absorptive NLO optical responses was analyzed for the first time.

Polyvinylidene fluoride and its copolymers are a well-known family of low-cost ferroelectric materials widely used for the fabrication of devices for a wide range of applications. A biocompatibility, high optical quality, chemical and mechanical durability of Poly(vinylidene fluoride&ndash, trifluoroethylene), (P(VDF&ndash, TrFE)), makes it particularly attractive for designing of effective coating layers for different diagnostic techniques. In present work, the nonlinear optical characterization of P(VDF-TrFE) coating films deposited onto a glass substrate was done. Advantages of the coating application for cells/substrates in the field of multiphoton imaging the efficiency of such coating layer for long-duration characterization of so-called harmonic nanoparticles (HNPs) were shown. It was analyzed the influence of glass surface protection by P(VDF-TrFE) film from an effect of HNPs sticking to the walls of the flow-cell, for effective studying of the optical harmonics generation efficiency of HNPs making the analysis more robust.

Mixed barium‑strontium Nd:phosphate glasses of composition: 58P2O5–13K2O–8Al2O3–4B2O3–2.5La2O3–2SiO2–0.5Nd2O3–12(Ba1–xO/SrxO) with a different degree of molar substitution x were prepared. Optical properties of these glasses were examined by UV–Vis-IR and photoluminescence (PL) spectroscopies. Considering IR spectra, it was suggested a certain contribution of oxygen defects in the optical properties of glasses. UV–Vis absorbance and PL emission spectra owing to the internal f–f electron transitions of Nd3+ ions were shown a complex character of electronic processes. The result of a comprehensive analysis of the optical scattering indicatrices has revealed non-monotonic variations of the scattering efficiency against the ratio of Sr to Ba that is correlated with the suggested content of the oxygen defects in the mixed glasses. A cubic nonlinear optical (NLO) response under the pulsed laser radiation self-action at 1064 nm shows that the self-defocusing effect increases with the molar fraction of Ba. For a continuous wave laser excitation at 1064 nm, the most efficient NLO refractive response with Re(χ(3)) = 2.9 × 10−3 esu was obtained in the pure strontium Nd:phosphate glass, being classified as a promising for NLO applications.

Present paper is devoted to the investigation of the nanosilicon films internal structure effect on optical properties. Atomic force microscopy results reveal that the films with different thickness have fundamentally different grain size distribution (samples with the film thickness less than 50 nm have single-mode grain size distribution, while samples with the film thickness more than 50 nm have multi-mode distribution of grain size). The correlation between grain size of nanosilicon films, photoluminescence and scattering indicatrix was shown. Well-isolated vibronic structures were observed on the ultraviolet–visible photoluminescence spectrum from nanosilicon films with the thickness more than 10 nm. The photoluminescence spectra in the red range correlate with the nanosilicon grain size distribution due to the effect of the quantum confinement. However, due to the complex shape of the grains mathematical modeling of photoluminescence spectrum is complicated. Both scattering indicatrix and photoluminescence reveal the multi-mode grain size distribution of the films with thickness more than 50 nm. The comparative analysis of theoretical results of optical radiation scattering by nanosilicon films with experimental ones is illustrated. Mathematical modeling of the scattering indicatrix shows the correlation of average grain size from scattering and photoluminescence data.

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In this study, we report soft and solvothermal methods for synthesis of zinc oxide nanoparticles (ZnO NPs). Both methods involve a precursor and are carried out at the middle low-temperature regime. The effect of different solvents on the ZnO NPs properties was studied. The nonlinear optical (NLO) response of the NPs was analyzed by the self-action of picosecond laser pulses at 1064 nm and by second harmonic generation (SHG) of a femtosecond laser pulses pump at 800 nm. The luminescence was studied within UV-visible ranges. It was shown that the NLO response efficiency significantly depends on the solvent. The obtained SHG efficiency of small (~2 nm) ZnO NPs is comparable to the one obtained for large (~150 nm) commercial ZnO NPs. The observed results are important for the application of the ZnO NPs in biolabeling. Electronic supplementary material The online version of this article (doi:10.1186/s11671-017-1934-y) contains supplementary material, which is available to authorized users.

For the first time, the diagnostics of oxyorthosilicates single crystals based on self-action of picosecond range laser pulses at 1,064 nm (1.17 eV) has been performed. High sensitivity of the photoinduced refractive index variation to the substitution of the Lu atoms by Gd in the LSO/LGSO crystalline host as well as to the admixture of Ce was found. The effect can be explained with different electron detrapping-recombination process efficiencies due to the resonant electron excitation from the deep traps in the gap attributed to intrinsic oxygen vacancies.

For the first time the diagnostics of oxyorthosilicates single crystals based on self-action of picosecond range laser pulses at 1064 nm has been performed. It was found high sensitivity of the photoinduced refractive index variation to the substitution of the Lu atoms by Gd as well as the admixture of Ce to the LSO/LGSO crystalline matrix. The effect could be attributed to the different electron detrapping-recombination processes efficiencies due to the oxygen vacancies excitation.

Linear and nonlinear optical properties of pHEMA-oxo-TiO 2 nanohybrids were studied. The reduction of refractive index with the increase of UV irradiation dose was observed. The TiO 2 nanoparticles concentration strongly affects the nonlinear optical response of the composite system.

Second harmonic generation efficiency enhancement in KDP single crystals with embedded anatase nanoparticles was accomplished in comparison with nominally pure KDP crystal. The enhancement effect occurs due the self-focusing of laser pump pulses.