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A glass composition using TeO2-K2TeO3-Nb2O5-BaF2 co-doped with Er2O3/Ho2O3 and Er2O3/Yb2O3 was successfully fabricated. Its thermal stability and physical parameters were studied, and luminescence spectroscopy of the fabricated glasses was conducted. The optical band gap, Eopt, decreased from 2.689 to 2.663 eV following the substitution of Ho2O3 with Yb2O3. The values of the refractive index, third-order nonlinear optical susceptibility (χ(3)), and nonlinear refractive index (n2) of the fabricated glasses were estimated. Furthermore, the Judd-Ofelt intensity parameters Ωt (t=2,4,6), radiative properties such as transition probabilities (Aed), magnetic dipole-type transition probabilities (Amd), branching ratios (ß), and radiative lifetime (τ) of the fabricated glasses were evaluated. The emission cross-section and FWHM of the 4I13/2→4I15/2 transition around 1.54 µm of the glass were reported, and the emission intensity of the visible signal was studied under 980 nm laser excitation. The material might be a useful candidate for solid lasers and nonlinear amplifier devices, especially in the communications bands.

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CONTEXT: In this study, we evaluate the geometrical, absorption, optoelectronic, electronic, nonlinear optical (NLO) and thermodynamic properties of dibenzo[b,def]chrysene molecule derivatives by means of DFT and TD-DFT simulations. In view of the aim of producing new high-performance materials for non-linear optics (NLO) by doping test, two types of doping were used. We obtained six derivatives by doping with organic dopants (Nitro, amide and ticyanoethenyl) and mixed alkali metal (potassium) and organic dopants. Doping with organic dopants produced molecules A, B and C, respectively when substituting one hydrogen with nitro (NO2), amide (CONH2) and tricyanoethenyl (C5N3) groups, while mixed doping involved considering A, B and C and then substituting two hydrogens with two potassiums to obtain compounds D, E and F respectively. The negative values of the various interaction energies calculated for all the doped molecules show that they are all stable, but also that molecules C and F are the most stable in the case of both dopings. The gap energies calculated at the B3LYP level of theory are all below 3 eV, which means that all the molecules obtained are semiconductors. Better still, compounds C and F, with gap energies of 1.852 eV and 1.204 eV, respectively, corresponding to decreases of 35.67% and 58.18% in gap energy compared with the pristine molecule, are more reactive than the other doped molecules. Mixed doping is therefore a highly effective way of narrowing the energy gap and boosting the semiconducting character and reactivity of organic materials. Optoelectronic properties have also been improved, with refractive index values higher than those of the reference material, glass. This shows that our compounds could be used under very high electric field conditions of the order of 4.164 × 109 V.m-1 for C and 7.410 × 109 V.m-1 for F the highest values at the B3LYP level of theory. The maximum first-order hyperpolarizability values for both types of doping are obtained at the CAM-B3LYP level of theory by C: ß mol = 92.088 × 10-30esu and by F: ß mol = 129.449 × 10-30esu, and second-order values are also given by these same compounds. These values are higher than the reference value, which is urea, making our compounds potential candidates for high-performance NLO applications. In dynamic mode and at a frequency of 1064 nm, at the CAM-B3LYP level of theory, the highest dynamic hyperpolarizability coefficients were obtained by C and F. Hyper-Rayleigh scattering ß HRS , coefficients of the electro-optical Pockel effect (EOPE), EFISHG, third-order NLO-response degree four-wave mixing γ DFWM , quadratic nonlinear refractive index n2 were also calculated. The maximum values of n2 are obtained by C (6.13 × 10-20 m2/W) and F (6.60 × 10-20 m2/W), these values are 2.24 times higher than that of fused silica which is the reference for degenerate four-wave mixing so our molecules could also have applications in optoelectronics as wavelength converters, optical pulse modulators and optical switches. METHODS: Using the DFT method, we were able to determine the optimized and stable electronic structures of doped dibenzo[b,def]chrysene derivatives in the gas phase. We limited ourselves to using the proven B3LYP and CAMB3LYP levels of theory for calculating electronic properties, and non-linear optics with the 6-311G + + (d,p) basis set, which is a large basis set frequently used for these types of compound. Gaussian 09 software was used to run our calculations, and Gauss View 6.0.16 was used to visualize the output files. TD-DFT was also used to determine absorption properties at the B3LYP level of theory, using the same basis set.

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The operation of photonic devices often relies on modulation of their refractive index. While the sub-bandgap index change through bound-electron optical nonlinearity offers a faster response than utilizing free carriers with an overbandgap pump, optical switching often suffers from inefficiency. Here, we use a recently observed metasurface based on mirror-induced optical bound states in the continuum, to enable superior modulation characteristics. We achieve a pulsewidth-limited switching time of 100 fs, reflectance change of 22%, remarkably low energy consumption of 255 µJ/cm2, and an enhancement of modulation contrast by a factor of 440 compared to unpatterned silicon. Additionally, the narrow photonic resonance facilitates the detection of the dispersive nondegenerate two-photon nonlinearity, allowing tunable pump and probe excitation. These findings are explained by a two-band theoretical model for the dispersive nonlinear index. The demonstrated efficient and rapid switching holds immense potential for applications, including quantum photonics, sensing, and metrology.

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Polymer blend hybrid nanocomposites are of great importance for future optoelectronic applications. This paper presents the preparation of new polymer blend hybrid nanocomposites based on PVC/PVP modified with Er2O3 nanoparticles. A low-cost solution casting method has been used to prepare the polymer nanocomposites at 0.0, 0.1, 0.3 and 0.6 wt% of Er2O3. X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, and environmental scanning electron microscopy (ESEM) measurements have all been used to examine the impact of a varying wt% of Er2O3 on the structural and optical characteristics of PVP/PVC polymer blends. The PVC/PVP polymer blend and Er2O3 nanoparticles showed a strong interaction, which was validated by XRD, FTIR, and Raman spectrum investigations. The SEM micrographs showed a remarkable complexation among the components of the polymer nanocomposites. The activation energies for thermal decomposition of PVC/PVP doped with different Er2O3 concentrations were less than that of the pure polymer film. The linear and nonlinear refractive indexes, dispersion energy, optical susceptibility and the energy gap values were found to be Er2O3 concentration-dependent. With an increase in Er2O3 concentration to 0.1 and 0.3 wt%, the dispersion energy and nonlinear refractive index improved, and thereafter decreased when the concentration was further increased to 0.6For the film doped with 0.1 wt% Er2O3, the optical band gap (Eopt) of the composite film enhanced by about 13%. The optical absorption measurements revealed clear improvements with the addition of erbium oxide. Higher refractive index values of PVC/PVP/Er2O3 films qualify the polymer blend as a cladding for electro-optic modulators. Our results indicated that the PVC/PVP/Er2O3 polymer films could be suitable for optoelectronic space applications.

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The nonlinear optical properties of zinc oxide nanoparticles (ZnONPs) in distilled water were measured using a femtosecond laser and the Z-scan technique. The ZnONPs colloids were created by the ablation of zinc bulk in distilled water with a 532 nm Nd: YAG laser. Transmission electron microscopy, an ultraviolet-visible spectrophotometer, and atomic absorption spectrophotometry were used to determine the size, shape, absorption spectra, and concentration of the ZnONPs colloids. The nonlinear absorption coefficient and nonlinear refractive index were measured at different excitation wavelengths and intensities. The nonlinear absorption coefficient of the ZnONPs colloids was found to be positive, caused by reverse saturable absorption, whereas the nonlinear refractive index was found to be negative due to self-defocusing in the ZnONPs. Both laser parameters, such as excitation wavelength and input intensity, and nanoparticle features, such as concentration and size, were found to influence the nonlinear optical properties of the ZnONPs.

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We report on the application of time-resolved inline digital holography in the study of the nonlinear optical properties of quantum dots deposited onto sample glass. The Fresnel diffraction patterns of the probe pulse due to noncollinear degenerate phase modulation induced by a femtosecond pump pulse were extracted from the set of inline digital holograms and analyzed. The absolute values of the nonlinear refractive index of both the sample glass substrate and the deposited layer of quantum dots were evaluated using the proposed technique. To characterize the inhomogeneous distribution of the samples' nonlinear optical properties, we proposed plotting an optical nonlinearity map calculated as a local standard deviation of the diffraction pattern intensities induced by noncollinear degenerate phase modulation.

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The nonlinear optical response of common materials is limited by bandwidth and energy consumption, which impedes practical application in all-optical signal processing, light detection, harmonic generation, etc. Additionally, the nonlinear performance is typically sensitive to polarization. To circumvent this constraint, we propose that orthogonal nanoantennas coupled to Al-doped zinc oxide (AZO) epsilon-near-zero (ENZ) material show a broadband (~1000 nm bandwidth) large optical nonlinearity simultaneously for two orthogonal polarization states. The absolute maximum value of the nonlinear refractive index n2 is 7.65 cm2∙GW-1, which is 4 orders of magnitude larger than that of the bare AZO film and 7 orders of magnitude larger than that of silica. The coupled structure not only realizes polarization independence and strong nonlinearity, but also allows the sign of the nonlinear response to be flexibly tailored. It provides a promising platform for the realization of ultracompact, low-power, and highly nonlinear all-optical devices on the nanoscale.

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We investigate the linear and nonlinear optical property of Morin (MN) at different concentration (1 × 10-6 and 5 × 10-6 M) within AOT reversed micelle prepared by water-in-decane microemulsion having a constant molar ratio of water-to-surfactant molecules of 40 (W = [H2O]/[AOT] = 40) as well as the function of mass fraction of nano-droplet (MFD) values of 0.01,0.04, 0.07, and 0.1 by using UV-Visible, Fluorescence, FTIR, and Z-scan techniques. The steady-state measurement indicates that the presence of microenvironment can greatly affect the tautomeric structure of morin and also Morin property in microenvironment depends upon the amount of oil and Morin concentration. The increase in dipole moment from the ground state to excited state in microenvironment indicate the change in the molecular structure on morin. Morin does not show any nonlinear absorption property but the nonlinear refractive index is observed as a function of Morin concentration as well as MFD values which are due to the thermal agitation of formed dimers. Morin nonlinearity.

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The dye of azo compound is prepared by coupling reaction of dizonium salt of sulfanilamide with benzoylacetone. The product is characterized by FTIR spectroscopy, Mass spectroscopy and 1H NMR spectroscopy. The geometries of the synthesized dye is optimized using B3LYP method and 6-31G (d,p) basis sets. Nonlinear optical properties are investigated theoretically by calculation of some quantum chemical descriptors using the DFT/B3LYP method with a 6-31G(d,p) basis set in comparison with urea as a standard. The UV-visible spectrum of synthesized azo dye are calculated using TD-DFT with B3LYP/6-31G(d,p) level. The nonlinear refractive index of the prepared dye is calculated via the diffraction ring patterns and Z-scan techniques using 473 nm visible, continuous wave laser light. The diffraction ring patterns are numerically simulated using the Fresnel-Kirchhoff theory with reasonable agreements. The property of optical limiting of the azo dye is tested.

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The effects of new treatments must be investigated in vitro before using clinically or in vivo. The aim of this study was to introduce the Z-scan technique as a fast, accurate, inexpensive, and safe in vitro method to distinguish the cytotoxic effects of various treatments. C6 and OLN-93 cell lines were prepared and treated with Temozolomide (TMZ), radiofrequency hyperthermia (HT), and chemo-hyperthermia (HT+TMZ). The cytotoxic effects of different treatments on both cell lines were evaluated using colony formation assay and Z-scan method. The results of colony assay showed that the surviving fraction (SF) of C6 cells treated with TMZ, HT, and HT + TMZ were significantly decreased compared to the control group. Whereas, hyperthermia treatment had no significant effect on the SF of OLN-93 cells. The results of Z-scan technique indicated that the control group of C6 cells had the negative nonlinear refractive index (n2). Whereas, the C6 cells treated with HT, TMZ, and HT + TMZ had the positive n2 index. The sign of n2 index in the control and HT groups of OLN-93 cells was positive but treatment of cells with TMZ and HT + TMZ changed the sign of it. Moreover, with increasing the cytotoxic effects of different treatments, the SF value of both cell lines decreased and the magnitude of n2 index increased. The results of Z-scan technique were completely in line with the results of colony assay. Therefore, Z-scan method could distinguish the cytotoxic effects of various treatments by examining the nonlinear optical properties of the samples.

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Membrane-bound or cytosolic light-sensitive proteins, playing a crucial role in energy- and signal-transduction processes of various photosynthetic microorganisms, have been optimized for sensing or harvesting light by myriads of years of evolution. Upon absorption of a photon, they undergo a usually cyclic reaction series of conformations, and the accompanying spectro-kinetic events assign robust nonlinear optical (NLO) properties for these chromoproteins. During recent years, they have attracted a considerable interest among researchers of the applied optics community as well, where finding the appropriate NLO material for a particular application is a pivotal task. Potential applications have emerged in various branches of photonics, including optical information storage and processing, higher-harmonic and white-light continuum generation, or biosensorics. In our earlier work, we also raised the possibility of using chromoproteins, such as bacteriorhodopsin (bR), as building blocks for the active elements of integrated optical (IO) circuits, where several organic and inorganic photonic materials have been considered as active components, but so far none of them has been deemed ideal for the purpose. In the current study, we investigate the linear and NLO properties of biofilms made of photoactive yellow protein (PYP) and bR. The kinetics of the photoreactions are monitored by time-resolved absorption experiments, while the refractive index of the films and its light-induced changes are measured using the Optical Waveguide Lightmode Spectroscopy (OWLS) and Z-scan techniques, respectively. The nonlinear refractive index and the refractive index change of both protein films were determined in the green spectral range in a wide range of intensities and at various laser repetition rates. The nonlinear refractive index and refractive index change of PYP were compared to those of bR, with respect to photonics applications. Our results imply that the NLO properties of these proteins make them promising candidates for utilization in applied photonics, and they should be considered as valid alternatives for active components of IO circuits.

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Two dihydropyridone compounds are synthesized from curcumin using microwave radiation. Both compounds were identified by their melting points and 1HNMR spectra. The nonlinear properties viz., nonlinear absorption coefficients and nonlinear refractive index of both compounds were calculated at wavelength 473 nm using the diffraction ring patterns and Z-scan techniques separately. The diffraction ring patterns evolved from circular symmetric to asymmetric due to convection current in the vertical direction. As a result of using Gaussian laser beam, the Fraunhofer approximation of the Fresnel-Kirchhoff diffraction, have led to successful simulation of the diffraction ring patterns with good quantitative and excellent qualitative agreements compared with experimental results. Optical limiting property has been tested in both compounds.

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Solvents as complex environments can induce considerable effects on the physical, chemical and biological properties of solute molecules. In this work, solvent polarity sensitive characteristics of two tautomers of different azo compounds were studied by using of spectroscopic and Z-scan techniques. In this case, nature and various molecular interactions contribution on the spectral behaviors of azo and hydrazone forms of selected samples were investigated by Kamlet-Abboud-Taft and Catalan models. Moreover, the obtained results of Z-scan indicate that self-defocusing, saturable and reverse saturable absorption features of azo dyes depend highly on substituents and molecular environment polarity characteristic. In this case, media polarity properties have the same effects on the third order nonlinear absorption coefficient and nonlinear refractive index values. Therefore, by measuring one of the third order nonlinear optical coefficients, it is possible to predict solvent polarity effects on the other nonlinear optical coefficient. The calculated dipole moments with high values in the molecular excited state also reveal the probability of molecular charge transfer characteristics. In this case, by excitation process, sample I indicate high dipole moment values in comparison to other samples. Therefore, the results can give useful information about the application of selected samples for designing various optical devices.

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In order to determine the level of cell damage in cancerous cells, current cytogenetic tests have limitations such as time consumption and high cost. The aim of this study was to demonstrate the ability of nonlinear refractive (NLR) index as a predictor of breast cell damage caused by magneto-plasmonic nanoparticle based thermo-radiotherapy treatments. MCF-7 breast cancer cells were subjected individually to the treatment of radiation, radio-frequency (RF) hyperthermia, and radiation + RF hyperthermia. These treatments were repeated in the presence of magneto-plasmonic nanoparticle (Au@IONP). The MTT and nonlinear optical assays were used to evaluate the damage induced by different treatment modalities. The results of MTT were correlated with Z-scan, as the magnitude of nonlinear refraction increased with higher intensity of induced cell damages. In this regard, the lowest cell viability (38 %,) and highest magnitude of NLR index (+28.12) were obtained from combination of radiation (at 4 Gy dose) and hyperthermia treatment in the presence of nanoparticles. The proposed optical index (NLR) indicated high capability and can be used as an auxiliary tool to monitor induced cell damage during different treatment strategies. This technique is fast, noninvasive, does not impose cost, and finally does not waste materials.

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A dihydropyridone has been prepared from butylamine and curcumin. A theoretical DFT study was conducted to determine the most stable conformer of the studied molecule (among three conformers) using the B3LYP/6-311+G(d,p) level of theory. This is assisted by the prediction of the 13C NMR chemical shifts of the conformers which then correlated with the observed 13C NMR chemical shifts. A TD-DFT study was conducted to analyze the electronic spectrum of the most stable conformer in order to determine the transitions responsible for the longer band in the electronic spectrum of the molecule. As well the frontier orbitals in the most stable conformer were analyzed to establish the density of donor and acceptor sites in the molecule that may be responsible for the nonlinear optical (NLO) properties of the studied molecule. Diffraction ring patterns were observed as a result of the use of visible, 473 nm, low power single mode laser beam traversed a thin cell containing solution of dihydropyridone. The nonlinear refractive index, n2, was determined based on the number of diffraction rings per a pattern observed and by the Z-scan technique and both results are compared. The upward convection heat effect appears to be responsible for the asymmetries observed in the diffraction ring patterns. The use of convergent and divergent laser beams has led to new types of diffraction ring patterns. Temporal evolution of each diffraction ring patterns was registered. The diffraction ring patterns experimentally obtained are numerically calculated using the Fresnel-Kirchhoff diffraction integral, with good qualitative and reasonable quantitative agreements.

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Hyperthermia treatment can induce component changes on cell. This study explored the potential of Z-scan to improve accuracy in the identification of subtle differences in mouse colon cancer cell line CT26 during hyperthermia treatment. Twenty-one samples were subjected individually to treatment of hyperthermia at 41, 43, and 45 °C. Each hyperthermia treatment was done in six different time (15, 30, 45, 60, 75, and 90 min). Two optical setups were used to investigate the linear and nonlinear optical behavior of samples. Prior to the Z-scan technique, all samples were fixed with 1 mL of 5% paraformaldehyde. The linear optical setup indicated that extinction coefficient cannot monitor cell changes at different treatment regimes. But the nonlinear behavior of CT26 in all hyperthermia treatment regimens was different. By increasing the time and/or temperature of hyperthermia treatments, change in the sign of nonlinear refractive index from negative to positive occurred in earlier time intervals. This phenomenon was seen for 41, 43, and 45 °C in 75, 60, and 45 min, respectively. The results showed that the Z-scan technique is a reliable method with the potential to characterize cell changes during hyperthermia treatment regimes. Nonlinear refractive index can be used as a new index for evaluation of cell damage.

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BACKGROUND: This study aimed to explore the potential of the Z-scan technique to improve accuracy in identifying SK-BR-3 and MCF-7 breast cancer cell lines. METHODS: Three in vitro samples were prepared for each breast cancer cell line. A closed-aperture Z-scan technique was used to measure the sign and magnitude of the nonlinear refractive index of each sample. Prior to the Z-scan, all samples were fixed with 1 mL of 5% paraformaldehyde. RESULTS: The sign of the nonlinear refractive indices of MCF-7 and SK-BR-3 breast cancer cell lines were negative and positive, respectively. The repeated Z-scan measurements for all samples of each cell line were similar. CONCLUSION: The results indicated that the proposed bio-optical method is a reliable method for characterizing differences in various breast cancer cell types. It is suggested that the nonlinear refractive index of cells be considered as an indicator for differentiating various breast cell lines from each other.

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A new optical method to discriminate benign and malignant oral tissue is reported. Twenty four tissue biopsy of patients tumor have been prepared in standard method without coloring process. The CW He-Ne laser beam interrogated the samples in optical setup. Linear absorption of tissues in laser wavelength measured and nonlinear behavior of tissue biopsies has been investigated by Z-scan setup. We used some simple optical instruments to focus on microsize region of biolayer to investigate less number of cells and to take repeatable test. Results show that the malignant samples have more attenuation than benign samples. Furthermore nonlinear refractive index (n2) of malignant biolayers has positive sign and n2 of benign biopsies has negative sign with the 10-8(cm2/W) order of magnitude. So this optical method may be used to discriminate malignant from benign tissues.

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Blue emitting 2-amino-4-(3, 4, 5-tri methoxyphenyl)-9-methoxy-5,6 dihydrobenzo[f]isoquinoline-1-carbonitrile (AMQC) dye was synthesized by one-pot multicomponent reactions (MCRs) of 3,4,5-trimethoxybenzaldehyd, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic and elemental analysis of synthesized AMQC was in good agreement with their chemical structures. Fluorescence polarity study demonstrated that AMQC was sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of AMQC. Dye undergoes solubilization in different micelles and may be used as a quencher and a probe to determine the critical micelle concentration (CMC) of SDS and CTAB. Nonlinear optical parameters of AMQC dye shows relatively lower nonlinear refractive index and nonlinear absorption coefficient at the power levels. Variation of n2 with concentration is linear in the concentration range used in the present study.