Birefringent and electro-optic effects in poled polymer films: steady-state and transient properties

The dependence of the second harmonic generation (SHG) signal of an amorphous polymer system containing nonlinear optical (NLO) chromophores on the polarizing electric field is investigated. It is shown that under a weak poling field condition, the SHG intensity is proportional to Ep2, provided that the polarizing electric field Ep is greater than a threshold field Es. Above Es, the macroscopic polar orientational order is established. The lengthening of the relaxation time for polar orientational order with increasing Ep is also observed. Theoretical analysis shows that the relaxation time is proportional to the polar order initially induced by the polarizing field. Experiments have been carried out to confirm the theoretical prediction.

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“…From Eq. (12), we obtain 4 E(t) =-EpS(t) (15) where S(t) is the Dirac delta function. Substituting Eqs.…”

Section: ) Kt Jmentioning

confidence: 98%

Polar order and relaxation of second order nonlinear optical susceptibility in an electric field polarized amorphous polymer

Wang

Guan

1993

The Journal of Chemical Physics

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“…In this paragraph, we show a theoretical model describing the nonlinear optical response of a medium constituted by nonlinear units (chromophores) dispersed in a linear matrix and oriented along a preferential axis [33,34]. We suppose that each molecule is identified by an intrinsic reference system with the axes named 1, 2, 3, and this system can be rotated in respect to the system that describes the whole macroscopic structure with the axes named x, y, z (laboratory axis).…”

Section: Steady-state Properties Of the Induced Electo-optic Coefficientmentioning

confidence: 99%

“…In order to describe these time-dependent phenomena, we introduce the rotational diffusion equation (Smoluchowski-Einstein) for a molecular dipole [33]:…”

Section: Transient Propertiesmentioning

confidence: 99%

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Fluorinated and Non-Fluorinated Electro-Optic Copolymers: Determination of the Time and Temperature Stability of the Induced Electro-Optic Coefficient

Belardini

2012

Applied Sciences

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Abstract:Organic fluorinated materials demonstrate their excellent electro-optic properties and versatility for technological applications. The partial substitution of hydrogen with fluorine in carbon-halides bounds allows the reduction of absorption losses at the telecommunication wavelengths. In these interesting compounds, the electro-optic coefficient was typically induced by a poling procedure. The magnitude and the time stability of the coefficient is an important issue to be investigated in order to compare copolymer species. Here, a review of different measurement techniques (such as nonlinear ellipsometry, second harmonic generation, temperature scanning and isothermal relaxation) was shown and applied to a variety of fluorinated and non-fluorinated electro-optic compounds.

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“…In this electret state the polymer manifests a variety of effects: pyroelectricity, piezoelectricity, birefringence, and electro-optical and second-order NLO response. [6][7][8][9][10] All these macroscopic properties of the electret are connected with the microscopic properties of NLO chromophores through the distribution function of chromophores by orientation, because the polarization is never ideal. The properties of the polymer obtained as a result of chromophore orientation may be used for the characterization (and control) of the orientational order of chromophores in the polymer.…”

Section: Introductionmentioning

confidence: 99%

Polymer Matrix Effects on the Nonlinear Optical Response of Incorporated Chromophore: New Analytical Models

Balakina

2006

ChemPhysChem

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A new approach aimed at the modeling of the nonlinear optical (NLO) response of a dipole chromophore incorporated into a locally anisotropic, deformable, polarizable polymer matrix is suggested. The general continuum methodology is used with a specific cavity ansatz being employed; the cavity is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the polymer medium. The suggested ansatz allows the electrostatic boundary value problem to be solved analytically, and the local field experienced by the chromophore in the polymer electret to be found. Four analytically solvable models, which correspond to two singular and two nonsingular models, are considered; in two of them the chromophore is characterized by singular dipole and quadrupole moments; the other two use the approximation of the electric moment of the chromophore with that of the polarized ellipsoid. The relation between the macroscopic polymer properties and the microscopic characteristics of the NLO chromophore is established. The compliance of the obtained formulas for the local field with those of the classical Onsager approach is analyzed, and their specific features are considered.

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Birefringent and electro-optic effects in poled polymer films: steady-state and transient properties

Cited by 170 publications

References 13 publications

Polar order and relaxation of second order nonlinear optical susceptibility in an electric field polarized amorphous polymer

Polar order and relaxation of second order nonlinear optical susceptibility in an electric field polarized amorphous polymer

Fluorinated and Non-Fluorinated Electro-Optic Copolymers: Determination of the Time and Temperature Stability of the Induced Electro-Optic Coefficient

Polymer Matrix Effects on the Nonlinear Optical Response of Incorporated Chromophore: New Analytical Models

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