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1

Separation of Electronic and Nuclear Contributions to the Third-Order Nonlinear Optical Susceptibilities of New Tetrathiafulvalene Derivatives Using Degenerate Four Wave Mixing

100%

Sahraoui B., Nguyen Phu X., Sallé M., Gorgues A.

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EN

We separate the electronic and nuclear contributions to the third-order nonlinear optical susceptibilities χ_{ijkl}^{〈3〉} using degenerate four wave mixing. This method allows to know the physical origin of the optical nonlinearities of new soluble tetrathiafulvalene derivatives and deduce the values of the second-order hyperpolarisabilities γ. The values of γ for the studied compounds are about 10^{5} greater than for CS_{2}.

2

The Third-Order Nonlinear Optical Susceptibility in Octupolar Molecule and its Dipolar Subunit

100%

Derkowska B., Sahraoui B., Nguyen Phu X., Andraud C.

Acta Physica Polonica A

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2001

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vol. 99

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issue 1

155-160

EN

The third-order nonlinear optical susceptibility χ^〈3〉 of octupolar molecule with three double bonds was measured using degenerate four wave mixing technique at 532 nm in tetrahydrofuran solution. For comparison, we also measured its analogous dipolar subunit. We found that the χ^〈3〉 value for octupolar molecule is about twice larger than its dipolar subunit.

3

Photoelectrical Behaviour of DNA:PEDT-PSS Functionalised Films

100%

Kažukauskas V., Pranaitis M., Krupka O., Sahraoui B.

Acta Physica Polonica A

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2011

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vol. 119

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issue 2

151-153

EN

We report investigations of functionalized DNA:PEDT-PSS films. The thermal activation energy of the conductivity near the room temperature was about 0.033 eV. The weak carrier trapping was identified by the thermally stimulated current method, proving the fast recombination of light-generated carriers. A "bistable" photoconductivity below the room temperature was evidenced upon the white light excitation. By cooling the samples down to 145-155 K the photoconduction was small. Below this temperature sudden increase of the photoconductivity was observed. Meanwhile by heating the photosensitivity remained enhanced up to 235-245 K. The slow relaxations of the current after the light excitation took place, the time constant of which reached several hundreds of seconds. Such phenomenon could presumably be attributed to the light-induced changes of the sample material morphology and/or associated variation of carrier transport conditions.

4

Optical Properties of Zn_{1-x}Mg_{x}Se Epilayers Studied by Spectroscopy Methods

88%

Głowacki G., Gapiński A., Derkowska B., Bała W., Sahraoui B.

Acta Physica Polonica A

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1998

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vol. 94

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issue 2

321-325

EN

Linear optical properties of the Zn_{1-x}Mg_{x}Se (0 ≤ x ≤ 0.4) alloys have been studied using reflectance, spectroscopic ellipsometry and photoluminescence measurements. The refractive indices of Zn_{1-x}Mg_{x}Se epilayers were investigated as a function of Mg composition (0 ≤ x ≤ 0.4). The energies of band gap E_{g} and spin-orbit splitting E_{g}+Δ, have been determined. These energies are shifted gradually to higher values with increasing Mg content.

5

Influence of Free Carrier Concentration on Nonlinear Absorption of n-Type ZnSe Crystals

88%

Sahraoui B., Chevalier R., Nguyen Phu X., Rivoire G., Bała W.

Acta Physica Polonica A

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1996

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vol. 90

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issue 5

1070-1074

EN

The dependence of nonlinear absorption at 532 nm of n-type ZnSe crystals upon annealing temperature and free carrier concentration is reported. The nonlinear optical absorption as well as the efficiency of degenerate four wave mixing of ZnSe are investigated. It is found that the magnitude of the nonlinear absorption decreases with an increase in the electron concentration. The nonlinear refractive index change is estimated.

6

Study of Second Harmonic Generation in KDP/Al₂O₃ Crystalline Nanocomposite

88%

Andrushchak N., Kulyk B., Göring P., Andrushchak A., Sahraoui B.

Acta Physica Polonica A

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2018

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vol. 133

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issue 4

856-859

EN

Crystalline nanocomposite KDP/Al₂O₃ was obtained by growth of KDP nanocrystals inside nanopores of amorphous alumina matrix (Al₂O₃) with pores diameter of 35 nm. Performed atomic force microscopy and X-ray diffraction analysis confirmed that Al₂O₃ matrix is filled up with a tetragonal phase KDP nanocrystals in preferred crystallographic orientation [100]. The nonlinear optical response was studied by means of second harmonic generation via the Maker fringe technique employing picosecond laser pulses at wavelength of 1064 nm. The polarization dependent second harmonic generation response was observed mainly due to the macroscopic crystalline structure anisotropy of KDP/Al₂O₃ nanocomposite. The investigation of such type of nanocomposites which combine nanoscale nonlinear optical materials has a great importance since they may improve the performance of entire system.

7

Photoinduced SHG in Push-Pull Chromophores 1,3-dithiol-2-yliedene Moieties Embedded in Photopolymer Matrices

76%

Migalska-Zalas A., Makowska-Janusik M., Kityk I., Sahraoui B., Salle M., Gorgues A.

Acta Physica Polonica A

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2003

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vol. 103

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issue 2-3

293-300

EN

Photoinduced optical second harmonic generation was demonstrated in the several dithiole chromophore molecules with different degree of acceptor function. Theoretical quantum chemical simulations and experimental photoinduced second harmonic generation measurements showed that additional aromatic rings within the dithiole chromophore molecule play an important role in the pump-power dependencies of the second harmonic generation. Varying the presence of the aromatic rings one can achieve substantially different photoinduced second-order nonlinear optical properties.

8

Photoinduced Nonlinear Effects in C_{60}-2-thioxo-1,3-di thiole and C_{60}-TTF Derivatives

64%

Migalska-Zalas A., Fuks-Janczarek I., Dabos-Seignon S., Sahraoui B., Kityk I., Allard E., Kreher D., Cousseau J., Hudhomme P., Gorgue A.

Acta Physica Polonica A

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2003

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vol. 103

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issue 2-3

283-292

EN

Photoinduced effects in pure C_{60}:C_{60}-TTF and C_{60}-2-thioxo-1,3-dithiole cycloadducts are investigated using nonlinear optical techniques. We have studied photoinduced optical second harmonic generation, two-photon absorption, linear electro-optics, and quadratic electro-optic effect coefficient versus applied pressure (p) and temperature (T). We deduce the influence of the grafted substituents in pure C_{60} on the observed photoinduced effects. The obtained results illustrate clearly that the photoinduced nonlinear optics can be used as a tool to detect structural changes at low temperature in modified C_{60}. We have unambiguously demonstrated that, under the applied hydrostatic pressure up to 19 GPa and the temperature from 4.2 up to 150 K, the observed effects are essentially caused by the grafted TTF derivatives.

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Separation of Electronic and Nuclear Contributions to the Third-Order Nonlinear Optical Susceptibilities of New Tetrathiafulvalene Derivatives Using Degenerate Four Wave Mixing

The Third-Order Nonlinear Optical Susceptibility in Octupolar Molecule and its Dipolar Subunit

Photoelectrical Behaviour of DNA:PEDT-PSS Functionalised Films

Optical Properties of Zn_{1-x}Mg_{x}Se Epilayers Studied by Spectroscopy Methods

Influence of Free Carrier Concentration on Nonlinear Absorption of n-Type ZnSe Crystals

Study of Second Harmonic Generation in KDP/Al₂O₃ Crystalline Nanocomposite

Photoinduced SHG in Push-Pull Chromophores 1,3-dithiol-2-yliedene Moieties Embedded in Photopolymer Matrices

Photoinduced Nonlinear Effects in C_{60}-2-thioxo-1,3-di thiole and C_{60}-TTF Derivatives