Values Of Third-order Nonlinear Optical Susceptibility Research Articles

Enhancing the physical, optical and shielding properties for ternary Sb2O3–B2O3–K2O glasses

Ternary Sb2O3–B2O3–K2O glass system, with general composition of x Sb2O3–(70-x) B2O3–30 K2O (where x = 0, 10, 20, 30, 40, 50) were prepared using melt-quenching technique. Structures of these glasses were investigated using XRD analysis and FT-IR spectroscopy. The optical properties were investigated using the UV–Vis NIR JASCO (Model V-670) Double Beam Spectrophotometer. Different physical parameters, such as density (ρ), molar volume (VM), oxygen molar volume (VO) and oxygen packing density values (OPD) have been estimated. Also, the Gamma radiation shielding ability have been characterized for the investigated glasses using Phy-X/PSD software in the photon energy range (0.015–15 MeV). XRD analysis confirm the amorphous nature of the prepared glasses. The optical energy gap of SBK glasses is decreasing from 4 to 2.63 eV with increasing Sb2O3 content while refractive index is increasing from 2.17 to 2.5 because of increasing the non-bridging oxygens (NBOs) in the glass matrix. The molar refractivity (Rm), molar polarizability (αm) and the third-order nonlinear optical susceptibility values χ3 have been calculated, their values are found to increase with increasing Sb2O3 content. Glass density and molar volume values for the SBK glasses increase with increasing Sb2O3 content. Increasing the Sb2O3 concentration enhance the radiation shielding features of the prepared glasses against gamma rays and neutrons. Hence, the mass attenuation coefficient (MAC) increases from 8.6 to 35.4 cm2/gm while the half value layer (HVL) decreases from 0.036 to 0.0046 cm at 0.015 MeV as the Sb2O3 concentration increases from 0 to 50 mol%. The fast neutron cross section of the six investigated SBK glasses are (0.087, 0.092, 0.095, 0.091, 0.094 and 0.092 cm−1), respectively.

Tunable nonlinear optical enhancement of α-FeOOH nanorods/RGO composites

High-quality α-FeOOH nanorods/reduced graphene oxide (RGO) composites were prepared by a facile hydrothermal method. Crystal structure and optical properties of the composites were characterized by XRD, SEM, TEM, FT-IR, Raman, UV–vis, PL. These results of characterization showed that the composites were successfully prepared. The third-order nonlinear optical (NLO) properties of the composites were investigated by Z-scan technique under 30 ps laser at 532 nm wavelength with 10 Hz repetition. The composites had larger third-order NLO susceptibility compared to pure α-FeOOH nanorods and RGO nanosheets. The enhancement of NLO performance benefited from synergistic effect of local field effect and charge transfer between α-FeOOH nanorods and RGO. Moreover, the composite with the α-FeOOH nanorods:RGO weight ratio of 2:1 (S3) showed the most robust NLO response. Comparing with RGO, the value of third-order NLO susceptibility χ(3) of S3 was increased by around 60 times and the saturation intensity Isat was nearly decreased by 6 times as the modulation depth M highly increased, respectively. The improved NLO property of α-FeOOH nanorods/RGO composite indicated its possible application in optical switches, mode lockers and other NLO devices.

Optical, thermal and nonlinear optical properties of amaranth dye-doped sulphamic acid single crystals

The optically transparent single crystals of pure and amaranth dye-doped (0.1 and 0.2 mol%) sulphamic acid (SA) are grown by slow evaporation solution technique. The unit cell parameters of the grown crystals were calculated by single-crystal X-ray diffraction. The various planes and its crystallinity were analysed by powder X-ray diffraction studies. The presence of amaranth dye molecules in the grown SA crystal lattice was confirmed by energy dispersive X-ray analysis. The optical quality of the crystal was analysed by ultraviolet–visible analysis and it reveals that the grown crystals have the good optical transmission in the whole visible region. No weight loss observed up to 212 °C, 214 °C (0.1 mol%) and 215 °C (0.2 mol%) for pure and amaranth dye-doped SA crystals, respectively. The increasing hardness and laser damage threshold properties of the crystals may be due to the incorporation of amaranth dye in the SA crystal lattices. Photoconductivity analysis shows that the pure and doped SA crystals possess negative photoconductive nature. The third-order nonlinear optical susceptibility values also increased as an effect of amaranth dopant.

Ultrafast dynamics and third-order nonlinear optical response of meso-(2-thienyl)porphyrin derivatives

Meso-(2-thienyl) porphyrin derivatives were synthesized. Excited state reverse saturable absorption was observed at 532 nm while two-photon absorption was observed at 800 nm. The nonlinear optical properties are increased by introducing the donator of thienyl group. Meso-(2-thienyl) porphyrin derivatives showed good nonlinear response at low energy. High third-order nonlinear optical susceptibility values (10−10 esu) of metal-free porphyrin derivatives were obtained. The mechanisms of third-order nonlinearity were proposed by the pump-probe experiment. With the observed fast electronic nonlinearities the studied molecules are potential candidates for use as optical limiters or optical switches.

Measurement of third-order nonlinear optical susceptibility of polyurethane-containing silica nanocomposites by Z-scan method

ABSTRACTThe Z-scan technique with an Nd: YAG laser at 532 nm was used for detecting the nonlinear optical (NLO) properties of the polyurethane semi-open cell (PUSOC)/SiO2 nanocomposite foam. The synthesized foams are also characterized by SEM images and their microstructural features were analyzed. The origin of optical nonlinearity, in this case, may be related to the presence of the two-photon absorption effect and self-defocusing process. Furthermore, the measured values of third-order NLO susceptibility of the PUSOC/SiO2 nanocomposite foam were of the order of 10−7esu.