In this study, we present a systematic study of linear and nonlinear optical properties of Para Red with the aim of Z-scan technique and quantum mechanical calculations. The Z-scan experiments were performed using a 532 nm Nd: YAG (SHG) CW laser beam. Para Red exhibited a strong nonlinear refractive index, nonlinear absorption coefficient and third-order nonlinear susceptibility 3.487 × 10-6 cm2/W, 2.341 × 10-1 cm/W and 2.157 × 10-4 esu, respectively. Also, quantum chemical analysis was used for the calculation of the dipole moment µ, dipole polarizability α, anisotropy of polarizability Δα and molecular hyperpolarizabilities (β, γ). The results revealed that Para Red has large first and second hyperpolarizabilities. However, from the obtained results, it was found that Para Red can be a promising material for applications in the development of non-linear optical materials.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
W artykule omówiono budowę włókna światłowodowego, zdefiniowano profil współczynnika załamania w rdzeniu światłowodu oraz określono wpływ temperatury na wartość współczynnika załamania szkła optycznego. Korzystając z opracowanego w środowisku MathCAD modelu matematycznego światłowodu telekomunikacyjnego, określono wpływ temperatury na wartość współczynnika w jego rdzeniu, w zależności od długości fali świetlnej, stężenia molowego domieszki GeO2 oraz różnicy termicznej zmiany polaryzowalności i termicznej rozszerzalności objętościowej. Sformułowano wnioski dotyczące wpływu rozpatrywanych czynników na czułość temperaturową szkła optycznego o strukturze SiO2–GeO2 oraz przydatności tychże szkieł do realizacji polarymetrycznych czujników natężenia prądu wykorzystujących magnetooptyczne zjawisko Faradaya oraz rozłożonych czujników temperatury wykorzystujących wymuszone rozproszenie Rayleigha.
EN
The article discussed the construction of optical fiber, the definition of refractive index profile in the fiber’s coreand the influence of temperature on the refractive index of optical glass. Using the mathematical model of the single mode fiber, which was realized in an MathCAD application, the effect of temperature on the value of refractive index in their core, depending on the wavelength of the light, the molar concentration of GeO2 dopant and the difference between the thermal changes of polarizability and the thermal volumetric expansion were has been determined. Conclusions regarding the impact of the factors considered on the temperature sensitivity of optical glass structure SiO2–GeO2 and of the use of these glasses for the implementation of polarimetric current sensors used Faraday effect and distributed temperature sensors using simulated Rayleigh scattering have been formulated.
The electro-optical Kerr effect finds wide application in conformational analysis of molecules and molecular aggregates [1–5], particularly in cases where the standard X-ray and NMR techniques cannot be used. For instance, NMR allows to establish conformations of linear and cyclic unsaturated organic compounds. However, it is less effective in an analysis of molecular complexes, particularly of those that have several rotational symmetry axes. In such cases a combination of techniques based on molecular dipole moments, electro-optical Kerr effect, optical Kerr effect, IR spectroscopy, and Rayleigh scattering can be applied [6]. The foundations of conformational analysis of molecular complexes using several complementary physical approaches are developed in Ref. [7]. The electro-optical methods are particularly useful for an investigation of intramolecular interactions [8–18]. The strength, direction and other details of intramolecular interactions can be determined by analyzing the deviations of the experimental molar Kerr constant (mK) from its value calculated according to the tensor-additive scheme that operates with polarizability tensors of molecular cores and functional groups [19, 20]. For instance, using this approach it has been shown that weakening of conjugation in an electron donor-acceptor chain can lead to flattening of the molecular structure [21]. The Kerr constant is also very sensitive to intermolecular interactions [22–29]. In order to assess quantitatively an extent of the solvent effect on the mK values, both molecular and continuum models of solution structure have been used [30, 31]. The mK values are greatly affected by the mutual orientation of solvent and solute molecules, which interact by dispersive, inductive and dipole-dipole forces [32]. Hydrogen and donor-acceptor bonding have an even stronger influence on the mK values [33]. The equimolar mixtures approach developed in Ref. [34] allows to determine the molar Kerr constant (mK), dipole moment (m), equilibrium constant (K) and, ultimately, structure of a molecular complex based on measurements of the Kerr constant (B), dielectric permittivity (e), density (d) and refractive index (n) of a series of dilute solutions of the complex. Future trends in the development of the electro-optical methods in chemistry are discussed. Theories that relate the electric-optic proprieties of molecules with their reactivity are particularly important. Such theories should be able to predict the changes in the polarizabilities and dipole moments of bonds, molecules and molecular aggregates during the course of chemical reactions.
W pracy przedstawiono wyniki badań światłowodów polaryzacyjnych otrzymanych metodą pręt-rura i omówiono wpływ zmian współczynnika załamania na właściwości optyczne i polaryzacyjne. Dokonano analizy i porównania serii światłowodów, co pozwoliło na wyznaczenie wzajemnej zależności pomiędzy dwójłomnością, tłumieniem, aperturą numeryczną, a współczynnikiem załamania elementów naprężeniowych.
EN
In this paper, results of research of (obtained RIT method) polarization fibers were presented and influence of refractive index on the properties was discussed. Analysis and comparison of polarization fibers were achieved, what allows for appointment correlation between birefringence, attenuation, numerical aperture and refractive index of stress elements.
5
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
W pracy zbadano dwa związki ciekłokrystaliczne MHPB(H)PBC oraz MHPB(F)PBC wykazujące właściwości antyferroelektryczne, zsyntezowane w WAT. Wyznaczono szereg wielkości charakteryzujących fazę jak: kąt tiltu θ, polaryzację spontaniczną Ps w fazie anty- i ferroelektrycznej. Na podstawie pomiarów optycznych oraz densytometrycznych, korzystając z dwóch różnych procedur ekstrapolacyjnych, obliczono polaryzowalności (αL i αT) molekuł tworzących fazę ciekłokrystaliczną. Wartość momentów dipolowych wyznaczono z pomiarów dielektrycznych w fazie izotropowej (korzystając z równań Maiera - Meiera) oraz z modelowania komputerowego za pomocą programu Hyper Chem 5.0.
EN
Two investigated antiferroelectric liquid crystals, MHPB(H)PBC and MHPB(F)PBC, were synthesized [1] and some their physical properties were described earlier [2]. Apart from the above, MHPB(H)PBC and MHPB(F)PBC have been studied by means of dielectric, densitometric, refractometric and X-ray measurements. Spontaneous polarisation and tilt angle θ in ferro- (SmC*) and antiferroelectric (SmC*A) phases of MHPB(H)PBC and MHPB(F)PBC have also been invastigated. Transverse αT and longitudinal αL molecular polarizabilities have been calculated from the ordinarynO and extraordinary nE refractive indices and densityρ of MHPB(H)PBC and MHPB(F)PBC, using Neugebaure, Vuks and Lorentz wquations with both Haller and Subramhanyama extrapolation procedures. Effective values of the molecular dipole moment have been calculated from electric permittivity in the I phases of these compounds, using Maier and Meier equation.
Przy użyciu programu obliczeniowego GAUSSIAN 98 przeprowadzone zostały obliczenia kwantowo-chemiczne polaryzowalności [alfa], hiperpolaryzowalności [beta]° oraz momentu dipolowego [mi] dla benzoimidazolowych, bbenzoitazolowych i etylokarbazolowych pochodnych diazowych p-nitroaniliny, sulfatiazolu oraz sulfadiazyny. Najwyżwsze wartości [beta]° otrzymano dla pochodnych etylokarbazolowych (CARB-1) 63,56 10-30 esu, najniższe zaś dla pochodnych benzoimidazolowych (BIM-2) 19,70 10-30 esu. Wykazano wpływ budowy cząsteczki chromoforu zarówno na wielkość drugiej hiperpolaryzowalności jak i wielkości kryterium FOM (figure of merit). Udział wielkości [beta]° w kryterium FOM dla wszystkich chromoforów z wyjątkiem CARB-1 zawiera się w granicach 0,5-5%.
EN
The polarizability [alfa], first hyperpolarizability [beta]° and dipole moments [mi] of benzoimidazoles, benzothiazoles and ethylcarbazoles derivatives of p-nitroaniline, sulfathiazole and sulfadiazine was evaluated by ab initio (GAUSSIAN 98) quantum-chemical calculations. The highest values of [beta]° were obtained for ethylcarbazoles (CARB-1) 63,56 10-30 esu, the lowest results were obtained for benzoimidazole derivatives (BIM-2) 19,70 x 10-30 esu. Basing of the results of the quantum-chemical calculations the influence of the molecular structure of chromofores on hyperpolarizobility and FOM (figure of merit) was discussed. For the chromofore in question the contribution of [beta]° in FOM is in range of 0,5-5%, except for CARB-1.
Hydrogen-bonded chains may show very large proton polarizability due to collective proton motion if they are largely symmetrical. This result was first obtained with polylysine + dihydrogenphosphate and with polyglutamic acid + dihydrogenphosphate systems, respectively. These systems cause intense IR continua, demonstrating their large proton polarizability. This proton polarizability was studied in detail with intramolecular hydrogen-bonded systems and results of these studies are extensively discussed in this paper. Such hydrogen-bonded chains are very effective proton pathways in biology. They can easily be regulated by local electrical fields and by specific interactions. Two such pathways are discussed, the one in the L550 intermediate in the bacteriorhodopsin molecule and the pathway in the F0 subunit of the ATP synthase.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.