Photoinduced structural rela×ation and densification in sol-gel-derived nanocomposite thin films: implications for integrated optics device fabrication

Saravanamuttu, Kalaichelvi; Du, Xin Min; Najafi, S. Iraj; Andrews, Mark P.

doi:10.1139/cjc-76-11-1717

Cited by 30 publications

(36 citation statements)

References 6 publications

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“…In this sense, an interesting family that fulfills this requirement is that obtained from the copolymerization between a vinyl-functionalized trialkoxysilane precursor and methyl methacrylate (MMA). Hybrid compounds have been prepared by different methodologies to develop materials with adjustable transparency, refractive index and hardness [37][38][39][40]. However, to the best of our knowledge, there are no reports in the accessible literature, regarding its use as epoxy modifier.…”

Section: Introductionmentioning

confidence: 99%

Relationships between nanostructure and dynamic-mechanical properties of epoxy network containing PMMA-modified silsesquioxane

Zaioncz¹,

Dahmouche²,

Paranhos³

et al. 2009

Express Polym. Lett.

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Abstract.A new class of organic-inorganic hybrid nanocomposites was obtained by blending PMMA-modified silsesquioxane hybrid materials with epoxy matrix followed by curing with methyl tetrahydrophthalic anhydride. The hybrid materials were obtained by sol-gel method through the hydrolysis and polycondensation of the silicon species of the hybrid precursor, 3-methacryloxypropyltrimethoxysilane (MPTS), simultaneously to the polymerization of the methacrylate (MMA) groups covalently bonded to the silicon atoms. The nanostructure of these materials was investigated by small angle X-ray scattering (SAXS) and correlated to their dynamic mechanical properties. The SAXS results revealed a hierarchical nanostructure consisting on two structural levels. The first level is related to the siloxane nanoparticles spatially correlated in the epoxy matrix, forming larger hybrid secondary aggregates. The dispersion of siloxane nanoparticles in epoxy matrix was favored by increasing the MMA content in the hybrid material. The presence of small amount of hybrid material affected significantly the dynamic mechanical properties of the epoxy networks.

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Section: Introductionmentioning

confidence: 99%

Relationships between nanostructure and dynamic-mechanical properties of epoxy network containing PMMA-modified silsesquioxane

Zaioncz¹,

Dahmouche²,

Paranhos³

et al. 2009

Express Polym. Lett.

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“…In this paper, we report that a new self-trapped spatially and temporally incoherent species-a hybrid beam-forms in a photocrosslinkable organosiloxane [1,2]. This photopolymer, which undergoes free-radical polymerization and a corresponding increase in refractive index upon irradiation, can be classified as a self-focusing medium (Figure 1).…”

Section: Introductionmentioning

confidence: 89%

Coaxial Self-Trapping of White and Gray Regions of an Incandescent Field: A Bright Core with a Dark Cladding

Kasala

Saravanamuttu

2012

Physics Research International

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We report the generation of a self-trapped incoherent hybrid beam comprising a dark-sheathed bright core. The hybrid beam originates from refractive index changes in a photocrosslinkable organosiloxane, which allow simultaneous and cooperative selftrapping of a gray ring with a white core embedded in a broad incandescent beam. The core narrowed and increased in intensity while the encircling gray ring decreased in intensity until rendered very dark. This dark sheath improves light confinement in the bright core and protects it from interactions with nearby self-trapped filaments. This is the first example of a self-trapped hybrid beam, which is moreover spatially and temporally incoherent.

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“…The photopolymer sample was 6 mm thick, which corresponded to an optical path-length (OPL) of 8.82 mm. Employing an approximate value of 1.47 for the refractive index (n) of the photopolymer [25], the Rayleigh range (z R ) of the beam was calculated to 0.87 mm. To study self-phase modulation in the photopolymer and the dynamics of the diffraction rings, we monitored the spatial intensity profile of the beam at the exit face (z 6.00 mm) over time.…”

Section: Methodsmentioning

confidence: 99%

Diversity and slow dynamics of diffraction rings: a comprehensive study of spatial self-phase modulation in a photopolymer

Villafranca

Saravanamuttu

2012

J. Opt. Soc. Am. B

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Spatial self-phase modulation of a Gaussian beam in a photopolymer generated diffraction rings that propagated over unusually long distances (≫Rayleigh length) in the medium. Self-phase modulation was examined under negative, positive, and infinite wavefront curvatures (R) over different pathlengths. Resulting diffraction rings exhibited previously unobserved, slow dynamics, which could be directly monitored at the sample exit face. This study complements but differs fundamentally from previous ones that were predominantly carried out in thin films (≤Rayleigh length) and generated static diffraction rings, which were propagated through air and imaged in the far-field. In the photopolymer, an input beam with R < 0 generated diffraction rings with a dark center, which propagated through the medium while increasing in number, underwent filamentation, and finally transformed into a stable self-trapped beam. Diffraction rings generated under R > 0 bore a bright center and cyclically exchanged intensity with proximal diffraction rings. Statistical analyses of self-phase modulation at R ∞ identified diffraction rings, which (i) were superimposed with high order modes of a co-propagating self-trapped beam, (ii) resembled fingerprint-like rings, (iii) emerged sequentially, and (iv) possessed a bright center. Results were rationalized by combining self-phase modulation theory with the evolution of refractive index changes in the photopolymer. The findings expose a new facet of spatial self-phase modulation and the complex dynamics of diffraction rings that propagate over long distances.

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Photoinduced structural rela×ation and densification in sol-gel-derived nanocomposite thin films: implications for integrated optics device fabrication

Cited by 30 publications

References 6 publications

Relationships between nanostructure and dynamic-mechanical properties of epoxy network containing PMMA-modified silsesquioxane

Relationships between nanostructure and dynamic-mechanical properties of epoxy network containing PMMA-modified silsesquioxane

Coaxial Self-Trapping of White and Gray Regions of an Incandescent Field: A Bright Core with a Dark Cladding

Diversity and slow dynamics of diffraction rings: a comprehensive study of spatial self-phase modulation in a photopolymer

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