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The nonlinear absorption coefficient and reverse saturable absorption on optical limiting threshold behavior was exhibited by 1-((E)-(2,5-dichlorophenylimino)methyl)naphthalen-2-ol (E25DCM) under the Nd: YAG nanosecond laser (532 nm, 9 ns, and 10 Hz) excitation. E25DCM crystal was grown by the slow evaporation technique at ambient temperature. The crystal structure was identified using the single crystal X-Ray diffraction analysis E25DCM belongs to Orthorhombic system with space group P212121. The Fourier Transform Infrared Spectroscopy, 1H-NMR Spectroscopy, and 13C-NMR Spectroscopy have all been well correlated with E25DCM structure. The thermal behavior indicates that E25DCM stable up to 160 °C. Surface analysis explains the irregular arrangement of E25DCM. The UV–Visible spectrum showed the absorption of E25DCM at 325 and 340 nm, and moderate transmittance is observed at the level of 62%. The optical band gap, which results in blue emission, is shown in the fluorescence spectrum at a value of 3.97 eV. The efficiency of crystal has significantly improved in the Second Harmonic Generation (SHG).Based on the Nonlinear absorption coefficient and optical limiting value of E25DCM, this crystal can be classified as an excellent NLO material and also a best contender for the use in developed laser safety devices. [ABSTRACT FROM AUTHOR]

Abstra: Thermally stable erbium-doped barium tellurite [60TeO2–20ZnO–4BaF2–(16 − x)BaCO3–xEr2O3, 0 ≥ x ≤ 2] glasses have been investigated for their linear and nonlinear optical properties. Significant concentration-dependent effects of erbium have been observed in most of the properties. Structural changes have been related to the formation of non-bridging oxygen atoms. Non-monotonic changes in physical and optical properties around 0.75 mol% doping indicated the network breaking and void filling ability of rare earth ions. Radiative lifetime of 4I13/2 level increased with erbium concentration to 2.64 ms for x = 2, while the luminescence intensity for 1.5 μm emission corresponding to 4I13/2 → 4I15/2 transition decreased beyond 0.75 mol% indicating the concentration quenching effect in the sample. This indicates the need for suitable compositional tunability to achieve the maximum output at suitable doping levels of erbium. Samples showed reverse saturable absorption phenomena owing to two-photon absorption. Significant higher optical nonlinearity led to lower optical limiting thresholds with values between 2.749 and 3.930 × 1012 W/m2, indicating their effectiveness as good optical limiting materials along with their lasing ability. [ABSTRACT FROM AUTHOR]

Silver (Ag) nanoparticles (< 50 nm in size) embedded polystyrene (PS) nanocomposite (PS/Ag) foils were prepared with different wt % of Ag nanoparticles into the polystyrene (PS) matrix via the solution casting method. These were studied for nonlinear optical characteristics and optical limiting behavior. The crystal structure and presence of functional groups were confirmed using X-ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The surface morphology, elemental composition, and spatial distribution of PS/Ag nanocomposite foils were studied by FESEM micrograph with EDX and EDS mapping that confirmed the homogeneous distribution of Ag nanoparticles throughout the PS matrix. The surface topography and roughness of the nanocomposite foils were studied with Atomic Force Microscopy (AFM). The chemical composition of the PS/Ag nanocomposite foils were studied using Raman spectroscopy which confirms the presence of D and G bands in the spectrum. The Z-scan technique was exploited to measure the optical nonlinear parameters of as-prepared PS/Ag nanocomposite foils using a continuous-wave (cw) diode laser at the wavelength of ~ 520 nm. Reverse saturation absorption (RSA) was observed in both PS and PS/Ag nanocomposite foils with different wt % of Ag which is attributed to the two-photon absorption (TPA) process. The values of nonlinear absorption coefficient (β) and third-order nonlinear susceptibility (χ3) increase from 0.82 × 10–3 to 11.7 × 10–3 cm/W and 5.205 × 10–7 (e.s.u) to 32.521 × 10–5 (e.s.u) with increasing wt % of silver nanoparticles, respectively. The calculated values of nonlinear refraction ( n 2 ) and second-order hyperpolarizability ( γ h ) lie in the range of − 9.16 × 10–9 to − 3.709 × 10–7 (cm2/W) and 1.525 × 10–26–9.530 × 10–24 (e.s.u), respectively. The nonlinear optical (NLO) parameters of these nanocomposite foils are of great interest for photonic applications. The limiting threshold (TL) for these nanocomposite foils was reduced to 16 mW with wt % of Ag nanoparticles that facilitated the optical limiting applications. [ABSTRACT FROM AUTHOR]

Si–Au nanocomposites were synthesised by pulsed laser ablation of a silicon target in a HAuCl4 solution by Nd-YAG laser source with a wavelength of 1064 nm. The linear and nonlinear optical characteristics of the samples were studied along with their structural and morphological features. The nonlinear optical studies of synthesised Si–Au nanocomposites were carried out by a single-beam Z-scan technique using a 532 nm Nd: YAG laser source. Si–Au nanocomposites synthesised in the presence of trisodium citrate show enhancement in the nonlinear absorption and exceptional optical limiting activity, which can be explored for optical limiting applications. [ABSTRACT FROM AUTHOR]

The slow evaporation method has been used to grow hexamethylenetetraminium 3,5-Dinitrobenzoate hemihydrate (HMTNB) single crystals. The single crystal X-ray diffraction investigation confirmed the centrosymmetric space group P 1 ¯ and triclinic crystalline system of grown HMTNB crystals. The powder X-ray diffraction, 1H, 13C NMR, FTIR, and FT-Raman analysis validated the crystalline nature, molecular arrangement, and functional groups in HMTNB. The intermolecular hydrogen bonding interactions of the HMTNB system have been well understood with the help of Hirshfeld surface study. Lower cutoff wavelength (386 nm) and emission peaks (312, 438, and 482 nm) have been reported in optical absorption and photoluminescence investigations. The dielectric study has revealed that HMTNB has low values of dielectric constant and loss. The photoconductivity study showed that HMTNB has a negative photoconducting nature. The HMTNB has a negative refractive index, and the Z-scan study revealed self-defocusing nature. Optical limiting studies indicate the HMTNB crystal's optical limiting response. Quantum chemical calculations were used to establish inter- and intra-molecular charge transfer mechanisms, as well as the presence of N–H···O, O–H···O and C–H···O hydrogen bonding in HMTNB are discussed in detail. [ABSTRACT FROM AUTHOR]

Ni0.5−xMgxZn0.5Fe2O4 (x = 0.00, 0.05, 0.10 and 0.15) samples were prepared by the sol–gel method. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer and LCR meter. XRD results confirmed that the samples were free of impurities. The grain size continued to increase with the doping of Mg2+ ions. According to the VSM analysis of Ni0.5−xMgxZn0.5Fe2O4, the saturation magnetization (Ms) of the samples can increase to 94.80 emu/g by Mg2+ doping. In addition, the Ni0.5−xMgxZn0.5Fe2O4 samples also showed dielectric behavior that can be explained by polarization theory. Moreover, ZnFe2O4 sample showed favorable nonlinear optical absorption characteristics due to the internal magnetic interactions and the distribution of cations in the sublattices. These results indicated that the samples involved in this work have potential applications in high-density recording media and optical limiting devices. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) was synthesized successfully from dead leaves of neem trees using a novel synthesis method comprising combustion, washing, and drying. The synthesized carbonaceous material was subjected to systematic characterization analysis. The rGO material was subjected to X-ray powder diffraction analysis to determine the grain size and other structural parameters. The existence of defect and graphitic band was confirmed by FT-Raman analysis. The presence of a 2D band around 2700 cm−1 indicated the formation of multi-layered graphene. SEM analysis was used to examine the structural morphology of the synthesized material. FTIR spectra revealed the information about the spectral properties of rGO. Compositional analysis revealed the presence of carbon and other contents in the specimen. The title material may be used in optical power limiters, according to z-scan and optical limiting analysis. The results indicate that the cost of synthesis would be significantly reduced when done on a large scale, using this procedure. Furthermore, rGO produced by this method is environmentally friendly, nontoxic and has a high yield. [ABSTRACT FROM AUTHOR]

Semi-organic nonlinear optical single crystals of Hexaaqua-Cobalt (II) bis (p-Toluene sulfonate) (PTCO) were grown by slow evaporation technique at ambient temperature. Single-crystal X-ray diffraction analysis reveals that PTCO belongs to the monoclinic crystal system with centrosymmetric space group P21/n. Hirshfeld surface analysis manifests the NLO property of PTCO. FTIR analysis concludes the presence of CH3 and SO3 functional groups and the incorporation of water and cobalt in the crystal lattice. The UV–Vis–NIR studies and photoluminescence analysis corroborated the suitability of PTCO in various optical and NLO applications. Solid state parameters calculated using the dielectric constant ensure the higher third-order nonlinearity of PTCO. Title material exhibits the semiconducting behavior during the resistivity measurement, while heating. Thermal stability of PTCO up to 125 °C and mechanical stability were also studied. The self-defocusing and reverse saturable absorption of PTCO were studied by Z Scan analysis. [ABSTRACT FROM AUTHOR]

Non-centrosymmetric crystal system of Guanidinium Azoate (GUA) single-crystal sub-semi-organic category has been synthesized by slow evaporation process. The crystallographic information of the specimen was collected for using in single-crystal X-ray diffraction analysis and it belongs to the monoclinic crystal system with the noncentrosymmetric space group Cm. The powder X-ray diffraction data were also used to measure the crystallinity and purity of the GUA sample. The Hirshfeld surface analysis showed copious kinds of intermolecular interaction appearance in the specimen. The discrete vibrational modes and functional groups availability in GUA are vividly displayed with Fourier transform infrared and Fourier transform infrared Raman spectral analysis in the range 4000–400 cm−1. From the linear optical studies, the band gap and cutoff frequency of the GUA crystal are described to be 4.38 eV and 237 nm, respectively. Using transmittance data, various optical constants such as extinction coefficient (K), refractive index, optical conductivity, electrical conductivity, and susceptibility were determined. The emission behavior of the GUA specimen was perceived by the fluorescence emission spectra indicating that the crystal is suitable for the fabrication of red lasers. The complex dielectric constant and dielectric loss were distinguished as 323 K temperature with different frequencies. Dynamic light scattering was used to determine the size distribution. The Kurtz powder technique and the second harmonic generation were corroborated and it is 1.15 times higher than that of KDP. GUA demonstrates superior antibacterial activity against discrete standard bacterial strains (Pseudomonas aeruginosa, Escherichia coli, (G-Ve) Staph aureus, and Bacillus subtilis (G + Ve)). These researches demonstrated that GUA crystal could be valuable in biological and nonlinear optical applications. [ABSTRACT FROM AUTHOR]

Two-photon absorption induced optical limiting action was demonstrated in cytosinium benzoate (CB) under nanosecond laser (532 nm, 9 ns, and 10 Hz) excitation. Intensity dependent open aperture Z-scan experiment exposed the presence of reverse saturable absorption ascribed due to sequential two-photon absorption. Initially CB single crystals were grown at room temperature by slow evaporation solution technique. Single crystal XRD shows that CB belongs to monoclinic crystal system with P21/c space group. Fourier Transform Infrared spectrum was recorded to identify the presence of functional groups. Thermal studies shows that the crystal is stable upto 168 °C. Vickers microhardness studies confirm that the grown crystal was belongs to soft material category. Etching study shows linear rectangular etch patterns (5 s) and well defined stacking planes (10 s) for water etchant. Optical studies demonstrate that CB crystal possess lower cut-off (287 nm) and moderate linear transmittance in visible region. The optical energy band gap of CB crystal was estimated from photoluminescence studies as 3.1 eV. CB with higher two-photon absorption coefficient (1.26 × 10–10 m/W) and lower onset limiting threshold (1.92 × 1012 W/m2) can be a potential candidate for developing laser safety devices under nanosecond green laser excitation regime. [ABSTRACT FROM AUTHOR]

Efficacy of silver nanoparticles concentration and annealing durations on optical limiting and optical nonlinearities of borate based glasses bearing the composition (79.5–x)B2O3–15Na2O–5La2O3–0.5Sm2O3–xAgCl (mol%) was assessed by Z-scan approach under the pumping of visible light (532 nm) in nanosecond regime. The dual photon absorption parameter (α2) was elevated from 0.576 × 10−11 to 1.201 × 10−11 m/W with AgCl content from 0 to 0.5 mol%. This α2 further raised to 1.964 × 10−11 m/W when the optimized glass host heat treated at 450° C for 25 h. Similarly, the index of nonlinear refraction (n2) was enhanced from 1.642 × 10−19 to 2.532 × 10−19 m2/W as the AgCl content increased from 0 to 0.5 mol%. This n2 value in turn monotonously increased to 2.963 × 10−19 m2/W when optimized glass system annealed at 450° C for 25 h. The optical limiting threshold magnitude followed reverse trend compared to α2 and n2. The enhancement in nonlinear optical features and optical limiting efficiencies were related to field stimulated by Ag0 nanoparticles when excited with high energy radiation. However, the non-uniform local field generated when the glass nanocomposites heated for longer duration resulted the switching of nonlinear absorption. The nonlinear optical and optical limiting results infer the 0.5 mol% AgCl encompassing glass sample annelaed at 450 °C for 25 h is benificail for construction of power optical limiters to operate in the visible range. [ABSTRACT FROM AUTHOR]

In this work, nonlinear optical response of the graphene oxide and an ionic liquid immobilized on a magnetic graphene oxide composite (IMIP-MGO) was investigated experimentally by open and close aperture of Z-scan technique. Magnetic graphene oxide was synthesized during the in situ formation of magnetite nanoparticles in an aqueous emulsion of graphene oxide and it was physically functionalized with the ionic liquids. We observed that the prepared sample has a giant nonlinear refractive index and nonlinear absorption coefficient in comparison with bare graphene oxide. The prepared sample was utilized for the optical limiting application at the low power of visible range spectrum of laser beam at the wavelength of 532 nm. Our experimental results show that the IMIP-MGO has the suitable limiting properties for low power of CW laser beam with the optical limiting threshold value of 30 mw. [ABSTRACT FROM AUTHOR]

Single crystals of (E)-4-bromo-N'-(2,4-dimethoxybenzylidene)benzohydrazide (DMBB) have been grown by slow evaporation technique. The molecular structure of the grown crystal was confirmed by Single-crystal X-ray diffraction (SC-XRD) studies. The active functional groups present in the synthesised compound were identified by Fourier transform infrared (FTIR) spectroscopy. 13C and 1H-NMR chemical shift values are in good agreement with the theoretical results. The UV–Vis spectrum is used to examine the optical characteristics of the grown crystal. The HOMO and LUMO energies are predicted as − 5.8981 and − 1.7469 eV. The energy gap between HOMO and LUMO is 4.1511 eV. The natural bond orbital (NBO) analysis results state that the highest energy transfer occurs between the donor π(C14-C21) and acceptor π*(C15-C16). The first-order hyperpolarizability value of the synthesised compound is six times greater than that of urea. The Z-scan approach was used to investigate the nonlinear optical (NLO) behaviour and optical limiting characteristics. [ABSTRACT FROM AUTHOR]

In the current investigation, L-Proline Potassium pentaborate octahydrate single crystals are successfully grown from aqueous solution by slow evaporation technique at ambient conditions. Single-crystal X-ray Diffraction technique proves that the LPPPB crystal belongs to monoclinic crystal system. The optical transparency is analyzed by UV–Vis–NIR spectroscopic technique. It exhibits 92.7% transparency of the title compound with a wide band gap of 6.4 eV. The different types of vibrations such as symmetric stretching, asymmetric stretching, wagging, rocking, intramolecular hydrogen bond interaction, and scissoring vibrations are well established by FTIR technique. The Z-scan technique is employed to assess the nonlinear absorption and refraction behavior of the LPPPB crystal. It declares the saturable absorption and self-defocussing behavior. The hardness number of the LPPPB crystal is calculated by Microhardness Study. The creditability of the LPPPB crystal for nonlinear optical device applications is proved by simultaneous TG–DSC analysis. [ABSTRACT FROM AUTHOR]

A new solution casting method was used to produce zinc oxide/poly(methyl methacrylate) (ZnO/PMMA) nanocomposite (PNC) membranes with zinc oxide nanoparticles of different content. X-ray diffraction and scanning electron microscopy were employed to analyze the composite films, revealing that some PMMA and ZnO NP interactions reduce the nanocomposite crystallinity. SEM images proved the homogenous dispersion of ZnO through the polymeric matrix of PMMA. As the amount of ZnO elevated, the size of the ZnO particles grew larger and more agglomerated. A direct and indirect optical band gap of PNC films were studied, including Urbach's energy and ZnO surface plasmon band-resonance. The dielectric constant has greater values with increased ZnO nanoparticles loading (ZnO NP) because of increased polarization in the polymer matrix at a reduced frequency. With enhanced frequency and ZnO NP content, the AC conductivity tends to rise. The studied material showed an excellent behavior for the optical limiting by using laser sources of 533 nm than laser sources of 632.8. All the prepared ZnO/PMMA were applied for photodegradation of MB. 2.5 wt% ZnO/PMMA exhibits an effective photocatalyst with about 100% MB degradation within 80 min. Trapping experiments were carried out to determine the radicals responsible for degradation. ZnO/PMMA has been recycled and reused. It has been proved that ZnO/PMMA is a promising material in electronic, optoelectronic, and photocatalytic applications. [ABSTRACT FROM AUTHOR]

Adapting the solution growth method, l-cysteine cadmium chloride (LCC) crystal was synthesized, and by using a single-crystal X-ray diffraction analysis, orthorhombic system was confirmed. From the powder XRD pattern, the crystalline nature of LCC crystal was revealed. With the help of FTIR spectroscopy, various functional groups present in the LCC crystal were identified. The UV–Vis-NIR spectroscopy analysis indicates a lower cutoff wavelength of 244 nm with an optical band gap of 3.77 eV. The linear optical properties such as optical conductivity (σopt) and electric susceptibility (χe) are also evaluated. By conducting the test of mechanical analysis, the hard nature of the LCC crystal was identified. A higher thermal withstand capacity of 392 °C was determined using TG/DT analysis. During the process, the high-energy-laser withstand capacity of the material was analyzed by a laser damage threshold analysis and it was found to be 6.87 GW/cm2. Kurtz and Perry's method was used to measure the SHG efficiency and observed to be 2.32 times higher than KDP. The negative nonlinear refractive index of the LCC crystal was confirmed by Z-scan experiment and the nonlinear refractive index (n2 = 2.73 × 10–11 m3/W), nonlinear absorption coefficient (β = 6.111 × 10–5 m/W), third-order nonlinear optical susceptibility (χ3 = 1.229 × 10–9 esu). The optical limiting performance of the LCC crystal displays a linear variation output for varying input laser power in low intensities and the optical limiting threshold value was found to be 46.9 mW. Etching analysis confirms the dislocation growth mechanism of the grown LCC crystal. [ABSTRACT FROM AUTHOR]

A mixed solution of 2-aminopyridine and succinic acid, with a 1:1 molar ratio, was kept at room temperature to develop a 2-aminopridinium succinate succinic acid (2APSS) crystal. The crystal structure was confirmed and cell parameter values were carried out using single-crystal XRD analysis. A FTIR spectrometer was used to identify the various functional groups in the 2APSS crystal. UV–Vis–NIR spectral analysis displayed optical parameters of the 2APSS crystal, namely lower cut-off wavelength, percentage of optical transmittance and band gap energy. The estimated values of lower cut-off wavelength and band gap energy are 354 nm and Eg = 5.77 eV, respectively. The dielectric behaviour of the 2APSS crystal was analysed. The thermal properties, namely thermal stability and melting point of the crystal (159 °C), were found by employing differential scanning calorimetry. The 2APSS crystal soft material category was confirmed by Vicker's microhardness study. A photoluminescence study was implemented to find out the emission spectrum of 2APSS. To demonstrate the third-order susceptibility of the produced crystal, Z-scan technique were used. It is important that the title material has a variety of excellent physicochemical and nonlinear optical characteristics, which assist it in gaining recognition as a prospective candidate for nonlinear optical device applications. [ABSTRACT FROM AUTHOR]

In the present decade, the advancement in photonic applications has stimulated the scientific community to explore nonlinear optical characteristics of optical materials. The present report on the synthesized proton-shifted monohydrated organic salt (ABMPP) of 2-Amino-5-bromo-6-methyl-4-pyrimidinol (ABMP) and 2,3-pyrazinedicarboxylic acid (PDCA) explores the linear and nonlinear optical (NLO) characteristics. The linear optical characteristics of ABMPP dissolved in DMSO have been investigated using the recorded absorption and photoluminescence spectra. In addition, the 1H-NMR analysis has been executed for structural characteristics. The third-order nonlinear optical characteristics of the sample have been measured using the Z-scan technique with a 520 nm laser beam of CW diode laser. The coefficients of nonlinear absorption (β), nonlinear refraction (n2) with nonlinear optical susceptibility, χ(3), and second-order hyperpolarizability (γ) have been estimated for various solution concentrations and laser powers. The evaluated β, n2, χ(3), and γ are found to be of the order of 10−4 cm/W, 10−8 cm2/W, 10−6 esu, and 10−26 esu, respectively, and these parameters vary linearly with solution concentration as well as laser power. The NLO performance of the ABMPP compound reveals its potential in photonic and optoelectronic applications. Furthermore, the compound has been also assayed for optical limiting characteristics with the same radiation and it shows comparatively better limiting performance. Hence this material could be a viable candidate for optical limiting devices. [ABSTRACT FROM AUTHOR]

Single crystals of copper (II) complex of P-Toluene sulfonic acid (PTSC) suitable for photonic applications were grown by slow evaporation technique. Single-crystal X-ray diffraction analysis (SXRD) shows that PTSC crystallizes in monoclinic system with a centrosymmetric space group (P21/c). The presence of red hallows and blue bumps in the shape index of the Hirshfeld surface confirms the NLO activity of the material. Fourier transform infrared spectroscopy vibrational analysis inferred the functional groups present in the synthesized PTSC. The synthesized material has good mechanical properties, and tight atomic packaging with six water molecules reveals its possible utilization in device fabrication applications. The dielectric constant was found to be high due to the inclusion of Cu2+ in the crystal lattice. Linear optical parameters such as bandgap energy, refractive index, extinction coefficient, optical conductivity, electrical conductivity, optical electronegativity, and Urbach energy are calculated from Ultraviolet Visible (UV–Vis) spectral analysis which depicts that the grown PTSC has high optical activity and can be used in the photonic application. The violet and green emission nature of PTSC was examined through Photoluminescence emission studies. The intensity-dependent third-order non-linear optical absorption property of the title material was studied using Z-scan analysis and PTSC exhibits two-photon absorption-induced optical limiting action. The non-linear optical (NLO) behavior of PTSC suggests the possible use in laser-driven applications as it can effectively control the laser to safe level. [ABSTRACT FROM AUTHOR]

A promising organic nonlinear optical single crystals of pyridinium oxalate (1-) oxalic acid dihydrate (POOAD) was successfully synthesized to analyse its physiochemical properties. The grown crystal belongs to triclinic crystal system with space group P 1 ¯ and unit cell dimensions were found to be a = 7.17 Å, b = 9.79 Å, c = 10.26 Å. All interactions present in the crystal lattice were analysed by Hirshfeld surface analysis. Combined FTIR and Raman spectra of POOAD single crystal clearly suggested the active sites and authenticates the incorporation of oxalate part in the crystal lattice. NBO analysis elucidates that the structure was mainly stabilized by intermolecular hydrogen bond interaction. The nature of charges present in the material is theoretically investigated by Natural Population analysis. Absorbance maxima, optical window, optical bandgap, Urbatch energy, linear refractive index of POOAD crystal was estimated with the help of UV visible spectroscopy. Fluorescence studies shows POOAD exhibit green emission and its suitability for green light-emitting NLO devices. Global reactivity descriptors were calculated using HOMO- LUMO energy gap. MESP analysis visualize the effective inter molecular charge transfer interactions between the electrophilic and nucleophilic part which enhances the optical nonlinearity. The mechanical parameters such as yield strength, elastic stiffness, fracture toughness and brittle Index of the grown crystals is analyzed using Vicker's microhardness test. Laser damage threshold of POOAD crystal is calculated as 2.15 GW/cm2 and is higher than the reference material. Z-scan experiment with nanopulsed Nd:YAG laser shows POOAD exhibit two-photon absorption induced optical limiting action. Thus POOAD crystal with high thermal and mechanical stability can be utilized as laser safety devices against most sensitive green nanopulsed lasers. [ABSTRACT FROM AUTHOR]

A systematic study of structural, thermal, linear, and non-linear optical properties on 60TeO2–20ZnO–(16 − x)BaCO3–4BaF2–xTm2O3 (x = 0.25 to 2 mol%) glasses synthesized by melt-quenching technique is reported. Thermal stability of the samples was found to be around 100 °C, while their energy bandgap values varied between 3.08 and 3.57 eV. Measured properties showed a dominant effect of thulium ions in modifying the properties of the glassy matrix. Structural studies using Raman spectroscopy showed the presence of non-bridging oxygen (NBO) dominated by the matrix effect and also aided by the rare earth dopants, while the presence of hydroxyl impurities was elucidated from infrared spectroscopy. Optical absorption spectra showed characteristic thulium bands and the increment in spectroscopic quality factor calculated from measured absorption data indicating the lasing capability of the material. Luminescence spectra yielded two strong 3H4 → 3F4 and 3F4 → 3H6 emission transitions in the infrared region around 1460 nm and 1863 nm for all the samples, intensities of which were affected by increasing rare earth concentrations. Open aperture Z-Scan measurements indicated a reverse saturable absorption behavior for all the samples owing to two-photon absorption. Formation of more NBO led to the reduction of optical limiting threshold values from 3.91 × 1012 to 2.38 × 1012 W/m2 with thulium doping which indicated that this glass can be tuned to act as mid-infrared source as well as excellent optical limiter. [ABSTRACT FROM AUTHOR]

This manuscript deals with the investigation of the impact of target-to-substrate distance on the linear and nonlinear optical properties of a-plane oriented aluminum-doped ZnO (ZnO:Al) thin films synthesized by the pulsed laser deposition (PLD) technique. X-ray diffraction studies proclaim an increment in the crystallinity with a decrement in target-to-substrate distance from 6 to 3 cm, attributed to increased thickness, decrease in stress, and defect levels in the thin films. A relaxation in the stress induces a decrease in the energy gap (3.47–3.37 eV) with a reduction in target–substrate distance from 6 to 3 cm is observed from UV–visible spectroscopic analysis. Spectroscopic ellipsometry confirms an increment in the refractive index and extinction coefficient with a decrease in target-to-substrate distance. From the Photoluminescence spectrum, the presence of low defect levels in the ZnO:Al thin films prepared at a shorter target-to-substrate distance is observed. The induced absorption (RSA) and self-defocusing process of ZnO:Al thin films are revealed by open aperture and closed aperture Z-scan measurements at 532 nm wavelength. The optical limiting behavior of all the thin films strongly suggests their applicability in optical power limiting. Thus, the present study emphasizes the optimization of the target-to-substrate distance to tailor the structural, linear, and nonlinear optical properties of the a-plane oriented ZnO:Al thin films. [ABSTRACT FROM AUTHOR]

Crystal structure, physicochemical and intermolecular charge-transfer-enhanced third order nonlinear optical properties of a new metal-organic cocrystal { [ NiCl 2 (C 4 H 11 N 2) 2 (OH 2) 2 ] (Cl) 2 (OH 2) 2 n } (PNi) is reported. An intermediate piperazinium chloride created during the pH optimization reacts with the metal centre (Ni), forming mono-substituted piperazine metal-organic cocrystal. The PNi adopts octahedral coordination geometry with triclinic ( P 1 ¯ ) crystal system at its single crystalline phase. The crystal packing stabilization via O - H ⋯ Cl , C - H ⋯ Cl and O - H ⋯ O noncovalent charge-transfer interactions is observed from single-crystal X-ray diffraction analysis. The PNi single crystal is thermally stable up to 87 ∘ C. The H 2 O molecules tend to evaporate at lower temperatures bringing moderate, rather sufficient thermal stability for using the title material in lasing applications. Vickers microhardness study revealed that the title crystal belongs to the soft material category. Investigation on dielectric properties showed polar dielectric nature of the material with consistent electronic polarizability ( α = 1.11 × 10 22 cm 3 ). The optical bandgap of 5.17 eV from UV-DRS spectroscopic analysis shows PNi belongs to the wide bandgap material category. The third order nonlinear optical absorption (β ), nonlinear refractive index ( n 2 ) and third order nonlinear optical susceptibility ( χ (3) ) of PNi cocrystal using 532 nm CW DPSS laser are measured to be (0.067 ± 0.001) × 10 - 4 cmW - 1 , (0.211 ± 0.0057) × 10 - 8 cm 2 W - 1 and (0.511 ± 0.09) × 10 - 6 esu, respectively. Intermolecular charge-transfer interactions and electronic polarizability well influence nonlinear optical properties and are proved possible by calculating the intermolecular charge-transfer interactions at the B3LYP/6-31G(d,p) level of calculations. Further, the nonlinear absorption coefficient (β ) was found to vary with the laser intensities, explicitly indicating the presence of excited state absorption assisted sequential 2PA in PNi cocrystal. Low onset limiting threshold for nanosecond pulsed and continuous-wave laser irradiance ( (1.66 ± 0.02) × 10 12 Wm - 2 and (0.804 ± 0.02) × 10 03 Wcm - 2 , respectively) promotes the title material as an efficient candidate for optical limiting application. [ABSTRACT FROM AUTHOR]

We report pure potassium penta borate octa hydrate (PPB) and methyl orange dye-doped potassium penta borate octa hydrate (MOPPB) for optical limiting applications. The crystals were grown by slow evaporation solution growth technique at ambient conditions. The single crystal X-ray diffraction (SXRD) evinces the orthorhombic class of the pristine and MOPPB crystals. Formation of PPB and incorporation of MO dye in PPB was confirmed through Fourier transform infrared (FTIR) study. Calculated hardness number and stiffness constant with Vicker's Micro hardness study portrays the soft nature of the title crystals. The decrease in bandgap of MOPPB is due to the additional energy levels introduced between the valence band and conduction band which in turn increases the net polarizability of the crystal. Relative second harmonic generation (SHG) efficiency of pure PPB and MOPPB is 0.45 times and 0.40 times that of SHG output of KDP. Z-scan studies shows that both crystals show reverse saturable absorption (RSA) ascribed due to two-photon absorption (TPA) process. MOPPB [β = 1.68 × 10–5 m/W, n2 = 10.2 × 10–12 m2/W, χ(3) = 3.5 × 10–9 m2/V2] possess higher NLO coefficients than pure PPB [β = 0.98 × 10–5 m/W, n2 = 4.62 × 10–12 m2/W, χ(3) = 6.1 × 10–9 m2/V2] which assured the superiority of azo dye incorporation in PPB crystals. Pristine and MOPPB crystals depict the optical limiting (OL) behavior under continuous wave (CW) diode laser irradiation at 785 nm. Thus, the linear and nonlinear properties bestow the MOPPB single crystal as a versed material for OL devices used for the safeguard of optical components from laser damage. [ABSTRACT FROM AUTHOR]

2-amino-5-nitropyridine 4-chlorobenzoic acid (1:1) (2A5NP4CBA), a potentially useful organic adduct compound, has been synthesized and grown as optically transparent single crystals by conventional slow evaporation solution technique (SEST) for the first time in the literature. The formation of new crystalline material was confirmed by the single-crystal X-ray diffraction (SXRD) analysis and it belongs to the monoclinic crystal system. Fourier transform infrared (FTIR) spectrum has been recorded by the KBr pellet technique to determine the various vibrational functional groups in the title material. The powder X-ray diffraction (PXRD) and high-resolution X-ray diffraction (HRXRD) analyses have been carried out to reveal the phase purity and crystalline perfection of the grown crystals. The obtained full width at half maximum (FWHM) for (001) plane in the HRXRD spectrum indicates the excellent crystalline quality of the title 2A5NP4CBA single crystal. The recorded UV–Vis–NIR absorption and transmittance spectra reveal that the grown crystal possesses more than 70% of optical transmittance with the cut-off edge at 419 nm. The thermal analysis discloses that the grown crystal possesses good thermal stability of about 187 °C. To determine the appropriateness of the grown crystal for the high-power laser application, laser damage threshold (LDT) analysis has been carried out by Nd: YAG laser of wavelength of 1064 nm. The third-order nonlinear optical (NLO) coefficients, such as nonlinear absorption (β), nonlinear refraction (n2), and nonlinear susceptibility (χ(3)), have been evaluated by utilizing a solid-state laser of wavelength 532 nm. The calculated value of χ(3) is found to be excellent compared to other organic single crystals. The optical limiting threshold of the grown crystal is found to be 7.8 mW/cm2 when using the solid-state laser of wavelength 532 nm. [ABSTRACT FROM AUTHOR]

Keeping in view the fascinating properties of noble materials in the nanoscale, we synthesized nanocomposite materials from Au and Ag metals in the form of core/shell structure by a simple, eco-friendly, inexpensive, and fast method. This method is pulsed laser ablation of Ag plate immersed in chloroauric acid solution using Nd:YAG solid state laser (1064 nm, 7 ns, 10 Hz). Physicochemical investigations were performed by different techniques for structural, morphological and optical characterization of the prepared nanocomposite, including characterization of linear and nonlinear properties. Crystalline structure of Au and Ag was confirmed with Au in the shell and Ag in the core of the resulting nanocomposite. The nonlinear optical characterization of the prepared nanocomposite was investigated by Z-scan technique using the second harmonic of the same laser source. The prepared Au@Ag core/shell nanocomposite showed a tuning of nonlinearity characteristic property between that of the nanoparticles composed of Au or Ag. In result, this material could represent an advanced nonlinear material as a promising candidate for optical limiting applications. [ABSTRACT FROM AUTHOR]

A new organic nonlinear optical (NLO) material 2-(6-chloropyridin-3-yl)-N'-(2,3-dihydro-1,4-benzodioxin-6-ylmethylidene)acetohydrazide (CDA) has been synthesized by reflux method. Single crystals were grown by slow evaporation technique and the crystal structure was elucidated by single crystal X-ray diffraction method. Density functional theory (DFT) calculations at B3LYP/6–31+ + G(d, p) basis set was used to predict the molecular geometry and were carried out further to comprehend the electronic structure, vibrational spectra, natural bonding orbitals (NBO), frontier molecular orbitals (FMO) and molecular electrostatic potential (MEP). An optical transparency at the cut-off wavelength of 355 nm was determined by UV–Vis–NIR spectroscopy. Thermal behavior of CDA was studied by TGA/DTA analysis. The dielectric constant (ε), dielectric loss (tan δ) and AC conductivity as a function of frequency and temperature was studied. Second Harmonic Generation (SHG) efficiency of the CDA was determined using Kurtz and Perry powder technique and was 0.5 times greater than that of the KDP crystal. The third-order nonlinear optical properties were investigated in solution by Z-scan technique using a continuous wave (CW) DPSS laser at the wavelength of 532 nm. The title compound exhibited significant two-photon absorption (β = 2.228 × 10–4 cm W−1), nonlinear refraction (n2 = 1.095 × 10–8 cm2 W−1) and optical limiting (OL threshold = 2.511 × 103 W cm−2) under the CW regime. The nonlinear optical parameters were calculated using time-dependent Hartree–Fock (TDHF) method. The overall obtained results suggested that the studied CDA molecule could be a potential NLO material for frequency generator, optical limiters and optical switching applications. [ABSTRACT FROM AUTHOR]

The perovskite-based materials with optical tuning properties are very important for many practical applications such as the solid-state lighting technology, solar cell, and catalysis. In this work, we used the top-down method to prepare the two-dimensional (2D) (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (CPI, n = 1, 2) hybrid perovskite quantum dots (QDs), and reported that the 2D CPI QDs featured an emission band covering the ultraviolet (UV) and blue region, with almost all the emission intensity in the UV region. This UV emission spectrum, along with the UV absorption spectrum, means a strong quantum confinement, as revealed by the X-ray photoelectron spectroscopy (XPS). In addition, the nonlinear optical scattering and absorption properties based respectively on the optical and photoacoustic z-scan characterizations were observed in the 2D CPI QDs, the results of which revealed a two-photon absorption coefficient of up to 6.5 × 102 cm/GW. This work reveal the potential of 2D CPI QDs in the high optical limiting applications. [ABSTRACT FROM AUTHOR]

Doping at the possible A or B site in the ABO3 perovskite can alter the structural, morphological and optical properties of the compounds. Perovskite alkaline earth stannate BaSnO3 doped with Fe resulted in BaSn1-xFexO3 compounds having different concentrations (x = 0.00, 0.01, 0.02, 0.03, 0.05 and 0.07) were prepared by solid-state method. The Rietveld analyzes were performed to determine the phase purity and the changes in structural parameters. Morphological analysis identifies the formation of hexagonal nanorods with doping. The non-linear optical property of the prepared samples shows optical power limiting behavior. Magnetic property signifies the existence of ferromagnetic order and EPR studies reveal the possible ferromagnetic ordering of Fe-doped samples. Dielectric loss decreases with Fe doping and has a gradual decrease in the higher frequency regime and has applications in high frequency devices. [ABSTRACT FROM AUTHOR]

The present work reports the intermolecular charge transfer (ICT) between donor and acceptor substituted ethyl violet (EV) (Color Index: 42600) dye for nonlinear optical (NLO) and optical limiting (OL) applications. The functional groups of EV dye have been analyzed by FT-IR spectra and suggest that the ICT process occurs within the dye molecules. Third-order NLO characteristics of EV dye in aqueous solution were investigated by a 5 mW power continuous wave laser operating at 635 nm wavelength. The nonlinear index of refraction (n2), nonlinear coefficient of absorption (β) and third-order NLO susceptibility [χ(3)] of EV dye were found to be in the order of 10−7 cm2 W−1, 10−3 cm W−1 and 10−6 esu, respectively. The ground and excited-state absorption cross-sections of the experimental dye were calculated for ensuring the existence of reverse saturable absorption. The OL behavior of aqueous solutions of EV dye was studied, and the limiting threshold was substantially reliant on dye concentration. The obtained results revealed that the EV dye is a possible NLO material for future photonics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

The main aim of this work is to synthesize creatininium 2-chloroacetate (CR2ClA) single crystal by using slow evaporation technique and to analyze its structural, optical and mechanical properties with the aid of experimental and theoretical techniques. The Single Crystal X-ray Diffraction analysis (SXRD) is carried out to identify the structural parameters. Hirshfield surface analysis explains the interactions present in the synthesized material. The optical property has been examined by using UV–visible spectral analysis and the optical constants such as band gap energy, extinction coefficient and refractive index were evaluated. HOMO–LUMO and MESP maps were successfully generated and analysed. The emission behavior was analysed by fluorescence spectral analysis. Third order optical non linearity was confirmed by Z scan analysis and the theoretical nonlinear optical parameters are calculated and analysed. The optical limiting behaviour and laser damage threshold analysis explains the synthesized materials laser assisting property. Mechanical property of the material has been analysed by Vicker's microhardness analysis and the mechanical parameters such as yield strength and elastic stiffness illustrates the materials excellent atomic package. [ABSTRACT FROM AUTHOR]

A transparent organic crystalline material guanidinium nitrate (GuN) was fruitfully harvested. Structure of GuN was verified by SXRD and its monoclinic system with Cm space group. Optical nature of GuN was confirmed by T%, n, ∆n and optical limiting. Strength nature of the GuN was tested by optical and mechanical hardness. The energy gap, global reactivity descriptors, linear and non-linear optical parameters were calculated at B3LYP/6-31G (d,p) level. Second- and third-order effective non-linearity was deliberated experimentally. [ABSTRACT FROM AUTHOR]

Optical limiting is considered one of the significant unusual applications that attract the attention of many scientists. In this study, we synthesized a novel flexible composite of silicon (Si)-doped polyvinyl alcohol (PVAOH) for this purpose. The preparation of the present polymeric film with different Si weight percentage was prepared by casting technique. The X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis spectroscopy of X-rays (EDX), and Fourier-transform infrared spectroscopy (FTIR) have been carried out. Also, UV–Vis–NIR spectroscopy has been used to test the optical interpretation of the as-prepared films. The analysis of the structure reveals substantial integration between the two current phases. The SEM images created to the samples indicate an increase in surface roughness with the Si- substantive. The addition of Si to the virgin PVAOH has an impact on the optical properties such as the indirect optical energy gap (Eg), the arrangement of the localized state (Eu), absorption coefficient, and optical conductivity response. Depending on different models like Moss, Hervé–Vandamme, Ravindra, and Singh-Kumar, the relation between the refractive index and the energy gap has been explored. Besides, the linear together with nonlinear optical assets of PVAOH/xSi polymer composites were investigated. The limiting aspects of the sample absorption were explored by employing different wavelengths (635 and 532 nm) coming from the He–Ne and green diode laser sources. The PVAOH/0.1Si film revealed significant optical advantages along with high optical laser limitation, recommending this could be a petitioner for different nonlinear technological devices and laser shields. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) incorporated with various amounts of ammonium iodide salt (NH4I) composite polymer electrolyte films were prepared via the casting process. The XRD analysis, as a tool for structural investigation, confirms the polymer electrolytes formation. The transmittances of the studied samples are decreased with increasing NH4I fillers. The UV–Vis absorption spectra are shifted to the higher wavelengths, which indicate their importance for light shielding devices. The bandgaps decrease with the increase in NH4I content, attributed to the increase in the crystallite size. The calculated Urbach energy was found to increase with increasing NH4I salt fillers. The samples' optical limiting is carefully investigated using a He–Ne laser beam of wavelength = 632.8 nm. This result enhances light absorption behavior and makes the material suitable for optical UV-protection devices. The correlation between dielectric properties and conductivity is also understood and discussed. The dielectric permittivity ε' of the samples is associated with the dipole, and polarization increased with the addition of NH4I salt content as the particle size increased according to XRD analysis. AC impedance spectroscopy was carried out to disclose the PVA doped with NH4I polymer electrolyte films as a function of various NH4I salt fillers. The analysis via complex electric modulus gives abnormal behavior by adding NH4I salt content, where the minimization of the electrode polarization can be achieved. Our results indicate that the newly designed composite polymeric electrolyte films are commonly appropriate for electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Indium phthalocyanine chloride, InPcCl, in the form of thin films were prepared with different thicknesses by thermal evaporation technique. X-ray diffraction showed a hump at 2θ = 28°, which identified that the prepared InPcCl films have an amorphous structure. The particle size increased from 56 to 357 nm with increased film thickness as indexed by Atomic Force Microscope technique. The transmittance and reflectance spectral distribution of InPcCl films was measured through a range of 250–2500 nm of wavelength. The optical transition is indirectly allowed with two optical energy gaps (Eg1 = 1.37 eV and Eg2 = 2.84 eV) for InPcCl thin films, which are smaller than other phthalocyanine films. The dispersion parameters were calculated for the different film thickness of InPcCl films from refractive index analysis in the region of normal dispersion. The linear, third-order, non-linear refractive index and non-linear susceptibility have also been measured. The optical limiting response was evaluated for the InPcCl films under the He–Ne laser and a green diode laser. The InPcCl film of thickness 95 nm exhibits the highest output power values and the normalized power. This advanced result will hopefully apply to the field of photodiode devices in an industrial approach. [ABSTRACT FROM AUTHOR]

The Nonlinear absorption and its optical limiting properties of 2-methyl 4-nitroaniline-polymethylmethacrylate (2M4NA-PMMA) electro-spun nanofibers are investigated by Z-scan technique using Q switched Nd:YAG laser as an excitation source (532 nm, 5 ns, 10 Hz). Open-aperture measurements show that 2M4NA-PMMA nanofibers exhibit reverse saturable absorption. Intensity-dependent two-photon absorption coefficient demonstrates the presence of sequential two-photon absorption process involving real resonant intermediate states. The incorporation and orientation of 2M4NA in PMMA nanofibers are analyzed by XRD and it is found to range from 38 nm to 43 nm of crystallite size. SEM images illustrate the formation of smooth fibers using electrospinning by applying different voltages (12, 14, 17 kV). Ground-state absorption analysis shows that the nanofibers possess maximum absorption around 400 nm with a optical transmittance window (410–1200 nm) in the wide range of entire visible and NIR region. Lower optical limiting threshold (0.97 to 1.79 × 1012 W/m2) of 2M4NA-PMMA nanofibers ensures the suitability of optical fibers as optical limiters towards the development of laser goggles for pulsed green laser. [ABSTRACT FROM AUTHOR]

The crystal of zinc potassium aluminum sulphate nonadecahydrate (ZPASDH) was first time grown by the slow evaporation method. Powder X-ray diffraction (PXRD) study was used to evaluate the structure of ZPASDH crystal. Using Fourier transform infra-red (FTIR) analysis the functional groups were identified. The UV–Vis spectrum recorded for the grown ZPASDH crystal, from the spectrum optical cutoff wavelength is observed at 387 nm and the optical band gap was also determined. Thermo gravimetric analysis (TGA) was used for confirmation of thermal stability of grown crystal. Mechanical strength of the ZPASDH single crystal was confirmed by Vickers microhardness study. Third-order nonlinear refractive index (n2 = 1.11 × 10−9 cm2/W), nonlinear absorption coefficient (β = 5.31 × 10−5 cm/W) and optical limiting behavior of ZPASDH crystal have been determined by Z-scan technique. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of organic nonlinear optical active (NLO) single crystal of l-threoninium succinate (LTS) were carried out in this work. LTS crystal was prepared by slow evaporation technique using deionized water as solvent in a period of 82 days and the obtained LTS crystal was subjected to such characterizations as single-crystal X-ray diffraction analysis, UV–Vis–NIR spectroscopy analysis, FT-IR spectrum analysis, thermal analysis, second harmonic generation, and surface quality analysis. The third-order nonlinear optical properties of the LTS crystal were estimated at 532 nm using semiconductor laser source. Then it was employed for Z-scan analyzer to sense the nonlinear refractive index (n2), absorption coefficient (β), and third-order susceptibility (χ3). Through this analysis, this research calculated the n2 = 2.35 × 10–15 (m3/W), β = 1.3057 × 10–8 (m/W), and χ3 = 1.0571 × 10−13 (esu) were determined. The obtained results exhibited an appropriate variation in optical limiting behavior of the LTS material which saturates at higher intensities with respect to input and output power. The laser damaged threshold (LDT) technique enables the great resistivity toward optical high energy and it is found to be 52.7 mJ. [ABSTRACT FROM AUTHOR]

In this work, we report a simple, facile, environment friendly and green approach to synthesize silver nanoparticles using aqueous flower extracts of Hibiscus Tiliaceus L. The morphology (shape/size) and crystal structure of as-synthesized silver nanoparticles (NPs) were determined by transmission electron microscopy and x-ray diffraction. The UV–Vis spectroscopy was used to record the surface plasmon resonance peak, while spectro-fluorophotometry was used to examine the fluorescence emission spectra of silver NPs. Moreover, the optical nonlinearities of silver NPs were investigated using z-scan technique with low power argon laser beam at wavelengths 488 nm and 514 nm in continuous-wave regime and at 532 nm in the pulsed laser regime. Our results indicate that the nonlinear absorption in silver NPs is reverse saturation absorption of the order of 10–3 cm/W and the negative nonlinear refractive index was determined as of the order of 10–8 cm2/W. Moreover, the optical nonlinear properties were used to demonstrate optical limiting abilities of the synthesized silver NPs. The results presented in this study indicate that bio-synthesized silver NPs are excellent candidates as a nonlinear material and can be widely used for waveguide applications. [ABSTRACT FROM AUTHOR]

Semi-organic single crystal of ammonium bis (citrato) borate dihydrate (ABCBDH) was harvested by slow evaporation technique (SET). The nature of the solubility of the ABCBDH crystal has been investigated by the gravimetrical method with different temperatures. The structure of the crystal system (orthorhombic), lattice parameters and space group (Pbca) were confirmed by single-crystal X-ray diffraction. The crystalline nature of the ABCBDH crystal has been determined by powder X-ray diffraction and its planes were identified by morphology studies. FT-IR and FT-Raman were used to analyze the presence of the functional group in the grown sample. UV–Vis spectrum was used to determine the transmittance percentage and lower cut-off of the ABCBDH crystal. Laser damage threshold and photoconductivity studies were also carried out. The growth pattern and etch pit density of the crystal was analyzed by etching studies. The third-order nonlinear optical property of ABCBDH crystal was analyzed by Z-scan method and the corresponding nonlinear refractive index, absorption coefficient, optical susceptibility and optical limiting parameters were calculated. The third-order nonlinear susceptibility (χ3) of ABCBDH single crystal was found to be 9.1973 × 10−12 esu. [ABSTRACT FROM AUTHOR]

Diprotonated salt of bis(4-methoxyanilinium) adipate [2(C7H10NO) +·(C6H8O2)−] has been synthesized and its crystal has grown by solvent evaporation technique. Good quality of the grown crystal is subjected to single-crystal XRD and powder XRD analyses; it revealed the molecular arrangements, formation of hydrogen bonds, and crystalline nature. The grown crystal crystallizes in a triclinic crystal system, P 1 ¯ space group with Z = 2. Decomposition and thermal behavior have been analyzed by TG–DTA measurements. The mechanical properties and dielectric behavior have been investigated from Vickers microhardness analysis and LCR meter. Optical transmittance spectrum was recorded and the optical bandgap has been calculated by Tauc plot. Furthermore, grown crystal has been characterized for third-harmonic generation by Z-Scan technique. The calculated nonlinear refractive index (n2), nonlinear absorption coefficient (β), and nonlinear optical susceptibility (χ3) values of the grown single crystal were 7.10 × 10−8 cm2/W, 0.05 × 10−4 cm/W, and 10.09 × 10−6 esu, respectively. The self-defocusing behavior is performed by the positive value of the nonlinear refractive index. The nonlinear absorption coefficient value indicates that 4MAA crystal is an efficient optical limiter. [ABSTRACT FROM AUTHOR]

The l-glutamic acid thin films prepared using a lucrative process simplified spray pyrolysis (or) perfume atomizer technique. The absorption coefficient, refractive index, extinction coefficient, imaginary and real parts of dielectric constant, electrical and optical conductivity, optical polarization, electrical and optical susceptibility were inspected with spectrum of UV–Visible spectroscopy. The optical properties for varying molar concentration and wavelength were investigated to reveal the characteristic features of the chosen sample. In addition, the nonlinear optical constants, third-order susceptibility, nonlinear refractive index, nonlinear absorption coefficient, intensity dependent refractive coefficient and change in refractive index were also examined with Z-scan technique. The optical nonlinearities were also assayed using the Eclipse and f-scan experiments. The difference in the nonlinear optical responses relating to selected functional parameters has been considered significantly along with optical limiting behavior. [ABSTRACT FROM AUTHOR]

Homogenous (poly (6,6′-(2-hydroxy-5-(phenyldiazenyl)-1,3-phenylene) bis (methylene) bis (2-ethylphenol)) (PHPP) film has been properly deposited using the spin coating method. In this paper, the polymer film was characterized by Atomic Force Microscopy (AFM), histogram characterization, intensity distribution of the film, and scan of the microscopic surface. The bandgap E g value was investigated by different ways. The Nonlinear Refractive Index (NLR) and Nonlinear Absorption (NLA) of the Flu-doped polymer, PbPc-doped polymer, and CuPc-doped polymer are determined using the Z-scan technique. Experimentation was conducted via a 532 nm diode laser and 3.554 KW/cm2 incident laser intensity. The effects of concentration of dye-doped PHPP films on the behavior optical limiting have been discussed. Additionally, multiple induced self-diffraction patterns generated in dye-doped PHPP polymer films using the same diode laser were observed through the study. The thermooptic coefficient (dn/dT) of the Flu-doped polymer, PbPc-doped polymer, and CuPc-doped polymer has been formed equivalent to − 0.409 × 10−5 K−1, − 0.88 × 10−5 K−1, and − 1.133 × 10−5 K−1, respectively. [ABSTRACT FROM AUTHOR]

ABO3 perovskites show unusual property modifications by proper substitution at the A and B sites. Polycrystalline perovskite BaSnO3 samples doped with different concentrations of manganese (BaSn1−xMnxO3) were synthesized by solid-state reaction method. Rietveld refinement of XRD analysis confirmed the structure and phase purity of the synthesized compound. Diamagnetic-to-paramagnetic transition and optical bandgap tuning indicate the substitutional effect of Mn in the host BaSnO3 lattice. The strong reverse saturable absorption of the synthesized samples makes them ideal candidate for optical limiting applications. The frequency and composition-dependent dielectric studies reveal that Mn-doped BaSn1−xMnxO3 can be used for high-frequency device applications. The cycling retention in the specific capacitance of 96.2% at a current density of 25 mA/g even after 2500 cycles in Mn-doped BaSnO3 electrode can be used in energy storage devices for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Third-order nonlinear optical material 4-[(1E)-3-(3,4-dimethoxyphenyl)-3-oxoprop-1-en-1-yl]phenyl 4-methylbenzene-1-sulfonate (DMPMS) is crystallized by slow solvent evaporation technique. The crystal has inversion symmetry and belongs to monoclinic system with P 2 1 / c space group. The C–H⋯O/C–H⋯π intermolecular interactions will be large complementarity for molecular density/crystal packing. A comprehensive investigation for absorbance and emission properties has been performed. Thermal stability is up to 258 °C without any weight loss and calculated value of laser damage threshold is ≈ 12 GW/cm2. The DMPMS shows low dielectric constant value, about 4.42 at 1 MHz and electronic polarizability values in the order of 10 - 23 cm3. Furthermore, theoretical calculation has been performed using B3LYP and M06-2X functional. The static first-order hyperpolarizability parameter is 55 (B3LYP) and 34 (M06-2X) times that of urea. The total contribution of second-order hyperpolarizability is − 37.9 × 10 - 40 esu (in B3LYP functional) and − 25.77 × 10 - 40 esu (in M06-2X functional), respectively. Here, two-photon absorption mechanism is responsible for nonlinear absorption and co-efficient is found to be 28.3 × 10 - 12 m/W. In optical limiting study, limiting threshold is found to be 65 µJ. The real and imaginary third-order nonlinear optical susceptibility is of the order 10 - 12 esu . [ABSTRACT FROM AUTHOR]

In the present work, successful manganese oxide (Mn2O3) nanoparticles (NPs) were synthesized by a combustion technique, while the casting process was employed for the manufacturing of polymer nanocomposites with various weights of Mn2O3 based on Poly(Vinyl Alcohol), PVA. Multiple methods such as X-ray diffraction (XRD), HR-TEM, EDAX, EDS, SEM, FT-IR, DTA analysis, optical spectroscopy from UV to IR regions, and optical reduction (CUT-OFF) setup were used to characterize the structural, elemental chemical analysis, morphological, optical properties, and cut-off laser characteristic of nanocomposite samples. Mn2O3 nanoparticles have a crystallite size of 22.08 nm as calculated using the Debye–Scherer formula from XRD, while the HR-TEM shows a spherical particle of size 30–38 nm range. EDAX spectra and EDS mapping were used to detect the elemental particles of the nanocomposite. The external morphology of the films by SEM images shows an increase in the agglomeration size of the cluster with the percentage of Mn2O3 nanoparticles in PVA. FT-IR spectra show excellent incorporation between the matrix of polymer and the Mn2O3 via the hydroxyl group. Moreover, with increasing the doping rate of nanoparticles, the thermal stability of PVA increased. A significant change of optical transmittance, absorption edge, Urbach energy, and transition bandgap have been observed due to the influence of Mn2O3. The comparison between the bandgap values that have been estimated from Tauc's relation and thus resulting from optical dielectric loss indicates a direct allowed transition of electrons in the nanocomposites. The light is entirely UV–Vis absorbed by PVA with a high percentage of Mn2O3 nanoparticles. Moreover, the efficiency of the films to decrease the power of two laser beams (635 nm and 533 nm) has been observed. The flexible films of PVA with an elevated rate of Mn2O3 are considered a successful option for low-cost technologies of optical limiting. [ABSTRACT FROM AUTHOR]

Intensity-dependent nonlinear optical absorption and optical limiting behavior of Ni2+-doped (γ and β)-BaB2O4 nanostructures were examined by open-aperture Z-scan technique under nanosecond pulsed green laser excitation. Observation of reverse saturable absorption (RSA) with variation in nonlinear absorption coefficient as function of on-axis peak intensity ascertains the presence of sequential 2PA process (1PA + ESA). Due to the introduced near-resonant energy state through incorporation of Ni2+ ions, the material exhibits excited state absorption (ESA). Here, the observed sequential 2PA in Ni2+-doped γ-BaB2O4 involves the 1T1g(G) states of 3d8–3d8 and 1T1g(D) states of Ni2+, while Ni-doped β-BaB2O4 undergoes the electronic transition involving intraionic 3d8–3d8 transition of Ni2+ and self-trapped excitonic state of BBO. Interestingly, as the dopant concentration and on-axis intensity increased, 2PA coefficient was found to be increased. 0.05 M Ni2+-doped β-BaB2O4 nanostructures possess higher 2PA coefficient (2.31 × 10−10 m/W) and lower onset limiting threshold (0.79 × 1012 W/m2), which makes it a promising candidate for optical limiting applications. The result suggests that band structure tunability to induce excited state absorption with enhanced nonlinear absorption coefficient is possible through Ni doping in β-BaB2O4 nanostructures. [ABSTRACT FROM AUTHOR]

The compound preparation, crystallization, spectroscopic characterizations and third order nonlinear optical properties of an organometallic nonlinear optical cesium hydrogen tartrate (CT) single crystal is reported. The title compound was crystallized in orthorhombic crystal system with noncentrosymmetric space group P212121. The functional group and their vibrational states were analyzed by FTIR spectroscopy. The optical band gap was found to be 5.98 eV. The recorded photoluminescence was evident for inter-band defect energy levels in the title crystal. The calculated CIE coordinates on RGB color gamut shows the blue light emitting capacity of CT crystal. Nonlinear optical properties of the title material under continues wave and pulsed laser excitation is reported for the first time. The intensity dependent refractive index (n2), absorption coefficient (β) and third order nonlinear optical susceptibility (χ(3)) of CT under continues wave excitation were found to be 0.569 × 10−8 (cm2W−1), 0.265 × 10−4 (cmW−1) and 8.78 × 10−7 (esu) respectively. The variation of β was studied under pulsed excitation with varying peak intensities. The values were found to be 0.72 × 10−10 (mW−1), 0.68 × 10−10 (m/W−1) and 0.64 × 10−10 (mW−1) for peak intensities of 0.61 × 10−12 (Wm−2), 1.23 × 10−12 (Wm−2) and 2.46 × 10−12 (Wm−2) respectively which confirms the presence of effective two photon absorption in CT. The optical limiting threshold at three intensities mentioned above were found to be 1.36 × 10−12 (Wm−2), 1.55 × 10−12 (Wm−2) and 1.79 × 10−12 (Wm−2) respectively. The value of Meyer's index (n) by Vickers micro hardness test was found to be 3.74 and it shows CT crystal belongs to soft material category. The thermogravimetric analysis showed that the CT crystal is thermally stable up to 215 °C. The dielectric constant (ε), dielectric loss (tan δ), AC and DC conductivity as a function of frequency and temperature were studied. The superior mechanical, thermal and dielectric properties with intensity tunable optical nonlinearity of cesium hydrogen tartrate single crystal promotes it as a promising candidate for optical limiting application. [ABSTRACT FROM AUTHOR]

In current article authors aim is to present an insight on structural, opto-nonlinear-limiting properties of Cadmium sulfide (CdS) thin films affected by various concentrations of tellurium (Te) doping. Hence, the thin films of pure and Te:CdS were fabricated by spray pyrolysis technique by keeping the substrate at 300 °C. X-ray diffraction and FT-Raman spectroscopy analyses confirmed the hexagonal phase of CdS. The values of Lave, ρave and εave are found in range of 18–20 nm, 2.6–3 nm−2 and 1.7–1.9, respectively. Furthermore, the energy dispersive X-ray spectroscopy/scanning electron microscopy mapping (SEM) confirmed the presence and homogeneous doping of Te in CdS. SEM study shows that the fabricated films are free from any pin holes and possess very fine nanostructures. The optical transparency of grown films was noticed ~ 70%, which is quite impressive for colored materials. The absorption index, refractive index values are found in range of 0.04 to 0.25, 1.25 to 3.2 in 200 to 2500 nm wavelength region. The direct energy gap of CdS was noticed to be reduced from 2.44 to 2.35 eV (ΔEg = 0.09) with Te doping content. Photoluminescence emission spectra contains an intense green emission band at ~ 528 ± 4 nm. The dielectric constant and optical conductivity were noticed in range of 1.5 to 10 and 0.02 to 0.6 (× 105), respectively. The values of third order susceptibility and nonlinear refractive index was found of the order of 10−10 esu. The output power of the 532 nm laser passed from films is found to be reducing with increasing the Te content in CdS films. Hence, the deposited films of Te:CdS will be more applicable as optical limiter in sensor device protection from intense lights. [ABSTRACT FROM AUTHOR]

Casting technique was used to prepare nanocomposites of polyvinyl alcohol (PVA) and graphene oxide (GO). GO has been set up by Hummer’s method and characterized by SEM and X-ray spectroscopy. Samples have been designed to contain a different weight percent of GO as follows: (0.370, 0.926, 1.852, 2.778, 3.704, 9.259 wt%) inside PVA matrix under the homogenous ultrasonic system to have a highly dispersed GO in PVA matrix. The nanocomposites were described and analyzed by utilizing different methods such as UV-Vis-NIR, dielectric studies at room temperature and optical limiting properties. It is shown that the influence of the nanofiller leads to the increase in the absorption values while diminishing the optical band gap of both direct and indirect transition. The dielectric constant (ε′) and the dielectric loss (ε″) were studied within the frequency range from 3 kHz to 10 MHz and were found to be depending on the GO contents. The conduction mechanism for the studied samples can be described by the correlated barrier hopping. PVA/GO nanocomposites showed good optical limiting properties. The synthesized GO-doped PAV can be used in electronic and optoelectronic applications especially in battery electrolyte and dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]