SOLVENT EFFECTS IN THE DETERMINATION OF THE NONLINEAR OPTICAL PROPERTIES

2008 ◽  
Vol 17 (04) ◽  
pp. 511-520 ◽  
Author(s):  
A. MENDOZA-GARCÍA ◽  
J. L. PAZ ◽  
M. GORAYEB ◽  
A. J. HERNÁNDEZ ◽  
E. CASTRO ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Probability Distribution ◽  
Absorption Coefficient ◽  
Solvent Effects ◽  
High Intensity ◽  
Signal Intensity ◽  
Nonlinear Optical ◽  
Molecular System

The interaction between a two-level molecular system and a high intensity electric field under the influence of a solvent was analyzed through the OSBE. To solve these equations, the average of the coherence was performed, using a generalized Lorentzian approximation for the Voigt's function as a probability distribution. Applying the convolution theorem, we were able to find an analytical expression for the coherence, from which we calculate optical properties, such as the absorption coefficient, refractive index and emitted signal intensity. In this contribution, we show numerical results for these properties, calculated for a standard model of organic colorants, Green Malaquite.

THEORETICAL MODEL FOR THE CALCULATION OF OPTICAL PROPERTIES OF GOLD NANOPARTICLES

2010 ◽  
Vol 19 (03) ◽  
pp. 427-436
Author(s):  
A. MENDOZA-GARCÍA ◽  
A. ROMERO-DEPABLOS ◽  
M. A. ORTEGA ◽  
J. L. PAZ ◽  
L. ECHEVARRÍA
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Theoretical Model ◽  
Absorption Coefficient ◽  
Molecular System ◽  
Two Dimensional ◽  
Box Models ◽  
Solvent Environment ◽  
Absorption And Dispersion

We have developed an analytical method to describe the optical properties of nanoparticles, whose results are in agreement with the observed experimental behavior according to the size of the nanoparticle under analysis. Our considerations to describe plasmonic absorption and dispersion are based on the combination of the two-level molecular system and the two-dimensional quantum box models. Employing the optical stochastic Bloch equations, we have determined the system's coherence, from which we have calculated expressions for the absorption coefficient and refractive index. The innovation of this methodology is that it allows us to take into account the solvent environment, which induce quantum effects not considered by classical treatments.

scholarly journals NONLINEAR OPTICAL PROPERTIES AND OPTICAL POWER LIMITING OF THE PREPARED POLYMER BLEND POLY (3HT- Co - Th) - PM FILMS

2021 ◽  
Vol 5 (1) ◽  
pp. 1-10
Author(s):  
Imad Al-Deen Hussein Ali Al-Saidi ◽  
Hussein Falih Hussein ◽  
Numan Sleem Hashim
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Polymer Blend ◽  
Nonlinear Absorption ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Optical Power ◽  
Copolymer Poly ◽  
Optical Power Limiting

Poly (3 - Hexylthiophene - Co - Thiophene) copolymer was prepared by using the addition polymerization method. The Nonlinear optical properties and the behavior of the optical power limiting of the prepared polymer blend poly (3HT- Co - Th) - PMMA films were studied by using the z - scan technique for different weight ratios of the copolymer poly (3HT- Co - Th). In the present work, a continuous wave (CW) diode - pumped solid - state laser (DPSSL) of wavelengths 532 nm was used for the irradiation of the prepared film samples. The nonlinear optical parameters such as, the nonlinear refractive index (n2), the nonlinear absorption coefficient (β), and the      third - order - nonlinear optical susceptibility (χ (3)) of the polymer blend poly (3HT- Co - Th) - PMMA films were determined for different weight ratios of the copolymer poly (3HT- Co - Th). It is observed that the polymer blend poly (3HT - Co - Th) - PMMA films exhibit saturable absorption (SA) and self - defocusing effects, and this gives an indication that both, the nonlinear refractive index (n2) and the nonlinear absorption coefficient (β), have negative values. The obtained results indicate that the prepared polymer blend poly (3HT - Co - Th) - PMMA films are promising materials and can be considered as suitable materials for different optical and electronic applications.

Solvent effects in the nonlinear optical properties using the Voigt function

2016 ◽  
Vol 25 (02) ◽  
pp. 1650016 ◽  
Author(s):  
J. L. Paz ◽  
Luis G. Rodríguez ◽  
Juan F. Cárdenas ◽  
Cesar Costa-Vera
Keyword(s):  
Optical Properties ◽  
Solvent Effects ◽  
Nonlinear Optical ◽  
Molecular System ◽  
Random Variable ◽  
Nonlinear Optical Properties ◽  
Thermal Bath ◽  
Gaussian Distributions ◽  
Radiative Interaction ◽  
Voigt Function

Nonlinear optical properties of a two-level molecular system immersed in a thermal bath have been studied in the present work. Solvent effects were explicitly considered by modeling the non-radiative interaction with the solute as a random variable. The innovation of this treatment is that it allows us to take into account the environment, inducing quantum effects not considered by classical treatment. The major contribution of the methodology proposed in this work, is the implementation of an approximant to the Voigt function as a probability distribution, because it allow us to cover a wider range of possible interactions among the solvent and the molecular system by simple changing the parameters [Formula: see text] and [Formula: see text], associated to the variances of the Lorentzian and Gaussian distributions, respectively.

SYNTHESIS AND NON-RESONANT NONLINEAR OPTICAL PROPERTIES OF PUSH-PULL SIDE-CHAIN AZOBENZENE POLYMERS

2011 ◽  
Vol 20 (01) ◽  
pp. 1-13 ◽  
Author(s):  
K. FEDUS ◽  
V. SMOKAL ◽  
O. KRUPKA ◽  
G. BOUDEBS
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Nonlinear Optical ◽  
Side Chain ◽  
Side Group ◽  
Third Order ◽  
Active Molecule ◽  
Nonlinear Properties ◽  
The Third

In this work, we report preliminary results obtained for methacrylic polymers incorporating azobenzene side-group as nonlinear optical (NLO) active molecule. The trans-cis isomerization properties are discussed. The third-order non-resonant nonlinear refractive index (n2) and nonlinear absorption coefficient (β) are measured using the Z-scan technique at 1064 nm in the picosecond regime. The influence of different electron-acceptor groups in azobenzene moieties on the nonlinear properties is investigated.

Determination of Nonlinear Refractive Index and Two-Photon Absorption Coefficients of New Nanocomposite Materials Based on Biosilicates Using Z-Scan Method

2014 ◽  
Vol 1025-1026 ◽  
pp. 776-781 ◽  
Author(s):  
Dmitriy Proschenko ◽  
Alexandr Mayor ◽  
Oleg Bukin ◽  
Sergey Golik ◽  
Irina Postnova ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Nanocomposite Materials ◽  
Photon Absorption ◽  
Absorption Coefficients ◽  
Two Photon Absorption ◽  
Two Photon

Nonlinear refractive indexes and two-photon absorption coefficients of new biosilicate nanocomposite materials based on precursor tetrakis (2-hydroxyethyl) orthosilicate (Si-precursor THEOS) were determined by created portative automation measuring complex based on Z-scan technique. Influence of different additives on nonlinear optical properties such media is considered. Energy thresholds of forming filaments and the efficiency of conversion initial radiation in supercontinuum in the range 400-700 nm are considered.

scholarly journals USING Z-SCAN TECHNIQUE TO MEASURE THE NONLINEAR OPTICAL PROPERTIES OF PMMA/ZNO NANOCOMPOSITES

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Haider Mohammed Shanshool ◽  
Muhammad Yahaya ◽  
Wan Mahmood Mat Yunus ◽  
Ibtisam Yahya Abdullah
Keyword(s):  
Thin Film ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Zno Nanoparticles ◽  
Nonlinear Absorption ◽  
Nonlinear Refractive Index ◽  
Optical Switching ◽  
Nonlinear Optical ◽  
Nonlinear Absorption Coefficient

The study of nonlinear optical properties of polymer nanocomposites has been given increasing attention due its application in laser, communication and data storage technology. There is a need to enhance the understanding of all photonics technologies. In the current work, PMMA-ZnO nanocomposites as foils and as thin films have been successfully prepared. Casting method and spin coating were used to prepare them respectively. Nanocomposites were prepared by mixing ZnO nanoparticles with polymethyl methacrylate (PMMA) as the polymer matrix. Different contents of ZnO nanoparticles were used as the filler in the nanocomposites. The absorbance spectra of the samples were obtained. The linear absorption coefficient was calculated. The nonlinear refractive index and nonlinear absorption coefficient were investigated using a single beam Z-scan technique. A Q-switched Nd-YAG pulsed laser   (532 nm, 7 ns, 5 Hz) was used as a light source. Both thin film’s and foil’s samples showed peak absorption at 375 nm and increasing absorption with ZnO nanoparticles concentration. The nonlinear refractive index was in the order of 10-11 cm2/W for thin film samples and 10-12 cm2 /W for foil’s samples with a negative sign. In contrast, the nonlinear absorption coefficient is in the order of 10-6 cm/W and 10-7 cm /W for thin film and foil respectively. The figures of merit W and T were calculated in order to evaluate the suitability of the samples as optical switching device .However; they unsatisfied the requirements of optical switching devices but they can be considered as an excellent candidate for optical limiting.

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

scholarly journals Flexible Methyl Cellulose/Polyaniline/Silver Composite Films with Enhanced Linear and Nonlinear Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1225
Author(s):  
Ali Atta ◽  
Mostufa M. Abdelhamied ◽  
Ahmed M. Abdelreheem ◽  
Mohamed R. Berber
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Nonlinear Optical ◽  
Composite Films ◽  
Methyl Cellulose ◽  
Carbon Cluster ◽  
Nonlinear Susceptibility ◽  
Optical Parameters ◽  
Flexible Polymer

In order to potentiate implementations in optical energy applications, flexible polymer composite films comprising methyl cellulose (MC), polyaniline (PANI) and silver nanoparticles (AgNPs) were successfully fabricated through a cast preparation method. The composite structure of the fabricated film was confirmed by X-ray diffraction and infrared spectroscopy, indicating a successful incorporation of AgNPs into the MC/PANI blend. The scanning electron microscope (SEM) images have indicated a homogenous loading and dispersion of AgNPs into the MC/PANI blend. The optical parameters such as band gap (Eg), absorption edge (Ed), number of carbon cluster (N) and Urbach energy (Eu) of pure MC polymer, MC/PANI blend and MC/PANI/Ag films were determined using the UV optical absorbance. The effects of AgNPs and PANI on MC polymer linear optical (LO) and nonlinear optical (NLO) parameters including reflection extinction coefficient, refractive index, dielectric constant, nonlinear refractive index, and nonlinear susceptibility are studied. The results showed a decrease in the band gap of MC/PANI/AgNPs compared to the pure MC film. Meanwhile, the estimated carbon cluster number enhanced with the incorporation of the AgNPs. The inclusion of AgNPs and PANI has enhanced the optical properties of the MC polymer, providing a new composite suitable for energy conversion systems, solar cells, biosensors, and nonlinear optical applications.

Sign in / Sign up

Export Citation Format

Share Document