摘要:

The crosslinked polyurethane PU-VP was prepared by the reaction of poly[(phenyl-isocyanate)-co-formaldehyde] and hydroxy-functionalized hemicyanine-type NLO chromophore. For the poled and cured polymer theχ(2)value was 30.2 pm/V measured at a wavelength of 1.064 μm. Thermal stability studies performed on PU-PV sample by the second harmonic generation activity indicated a nearly no decay ofχ(2)value due to the lattice hardening of the polyurethane matrix with three bonding sites. The relaxation behaviors of aligned dipoles in PU-PV were also studied by varying poling and crosslinking conditions.

ISSN:1058-725X    

DOI:10.1080/10587259808044457

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Second-order nonlinear optical polyimides were successfully synthesized by Mitsunobu reaction of polyhydroxyimides with hydroxylated benzoxazole chromophores. These resultant fluorinated polyimides were fairly soluble in pyridine, cyclohexanone, and therefore could be easily spin casted for electrooptic thin films. The polyimides had glass transition temperatures of 175∼195 C, and the electro-optic coefficients were in the range of 8.5∼12.3 pm/V at 1.3 μm and showed long-term temporal stability

ISSN:1058-725X    

DOI:10.1080/10587259808044458

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

New second-order nonlinear optical polyimide was synthesized by posttricyanovinylation of N-phenyl containing polyimide. The tricyanovinylation inpara-position of aniline was well identified by1H-NMR spectroscopy. The polyimide had a high glass transition temperature of 218 °C, and showed an excellent thermal stability. The electro-optic coefficient (r33) and nonlinear optical coefficient (d33) was 38 pm/V (at 0.63 μm) measured by simple reflection method and 84 pm/V (at 1.06 μm), respectively.

ISSN:1058-725X    

DOI:10.1080/10587259808044459

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two different configurations, reflection and transmission, of Mach-Zehnder interferometer(MZI) are introduced for the measurement of the electro-optic coefficients in a poled polymer thin film. The MZI measurement of the electro-optic coefficients has an advantage of permitting the determination of the electro-optic tensor coefficients, r13and r33, independently, when compared with the single-beam polarization interferometer. In the reflection configuration of two beam interferometric measurement, a proper consideration of the optical path change, due to the reflection angle change, is found to be critical in determining the absolute value of the electro-optic coefficients, while the transmission configuration allows the independent determination of the electro-optic coefficients in the direction of the ordinary and the extraordinary optic axes.

ISSN:1058-725X    

DOI:10.1080/10587259808044460

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

By analyzing the mechanism of J-aggregate formation with a squarylium dye on the water surface, we succeeded to obtain a mono-molecular layer with an extremely large optical density (>0.3). Because of the homogeneous and fine structure of this film, an ultrafast nonlinear optical response exhibiting a two-dimensional mono-molecular layer nature was observed at room temperature.

ISSN:1058-725X    

DOI:10.1080/10587259808044461

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

By iodine doping, the structure of Pt(dmg)2is changed from the orthorhombic with one-dimensional metal chain to an amorphous-like state, which means that the doping induces fluctuation of metal-metal distance along the chain axis. This structural change is reversible; that is, the amorphous state turns back to the orthorhombic crystal by heating at 130°C, corresponding to the reversible change in optical properties.

ISSN:1058-725X    

DOI:10.1080/10587259808044462

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We theoretically and experimentally investigated the photoisomerization of azo chromophores and the resulting nonlinear optical response of transmission and four wave mixing through the two-energy-level model. The rising time constant of the transmission obtained by the model gave good agreement with that of the wave-mixing signal In addition, we tried to improve the time response by using photoactive polymers ionic-bonded with azo chromophores.

ISSN:1058-725X    

DOI:10.1080/10587259808044463

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Optical enhancement and control of the nonlinear optical (NLO) properties of organic compounds can be expected at the excited state because of changes in dipole moments and oscillator strength caused by electron density distribution different from that at the ground state. We constructed a novel measurement system of hyperpolarizability β at the excited state of molecules in solutions. The system was based on nanosecond Hyper-Rayleigh Scattering (HRS) method with CW laser excitation. In the HRS technique, a chromophore solution was irradiated by YAG laser beam of various intensities (frequency ω), and the scattered photons at 2ω were detected. The HRS intensity was proportional to the square of the incident laser intensity. The increase of HRS intensity forp-nitroaniline was observed in methanol solutions upon excitation with CW Ar laser at 457.9 nm. The β-value at the excited state was estimated.

ISSN:1058-725X    

DOI:10.1080/10587259808044464

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Spontaneous noncentrosymetric in-plane alignment of carbazole polymers is demonstrated. The alignment was taken place during film preparation process, one is thermal treatment and the other is flow casting.

ISSN:1058-725X    

DOI:10.1080/10587259808044465

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Optical polymers which exhibit good thermal stability, refractive index controllability, and low optical loss in the optical communication wavelengths were developed by using chloro-fluorinated poly(arylene ethers).

ISSN:1058-725X    

DOI:10.1080/10587259808044466

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor