摘要:

In situ observation system of second harmonic generation (SHG) during vacuum deposition has been constructed. It allows us to observe SHG from transmitted and reflected directions. The advantages of the system is summarized in the following two points: (1) Detailed dependence of SHG on film-thickness can be easily obtained. (2) The measurement can be achieved without exposing films to the atmosphere. This system was applied to vacuum evaporated films of copper phthalocyanine (CuPc) to clarify the origin of SH activity in such a centrosymmetric molecule. We suggest the importance of quadrupolar contribution on the basis of the thickness dependence of SHG and the comparison with the theoretical analysis.

ISSN:1058-725X    

DOI:10.1080/10587259508033964

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Novel silicon substituted PPV derivatives, poly[2,5-bis(trimethylsilyl)-1,4-pheylenevinylene] (BTMS-PPV) and PPV copolymers, were synthesized through water-soluble precursor route, and their electrical and third-order nonlinear optical properties were studied. The BTMS-PPV films could not be doped with 12but doped with FeCI3to show the electrical conductivity of 5.0 × 10−4S/cm. The conductivities of FeCI3−doped copolymer films ranged from 5.0 × 10−1to 25 S/cm depending on their copolymer compositions and draw ratios. The third-order nonlinear optical susceptibility, χ(3)(-ω;ω,ω,-ω), was also investigated by the degenerate four-wave mixing (DFWM) measurement technique at 602 nm. The calculated χ(3)value of BTMS-PPV was 5.8 × 10−10esu. The photoluminescence spectrum of BTMS-PPV was observed and it showed its emission in pure green region.

ISSN:1058-725X    

DOI:10.1080/10587259508033965

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In order to improve the third-order nonlinear optical properties of polydiacetylenes (PDAs), various types of PDAs with π-conjugation between the main chain and pendant side groups were synthesized by crystal engineering for solid-state polymerization. It was clearly seen the optical properties of PDAs could be modified by an increased of π-electrons per the repeating units.

ISSN:1058-725X    

DOI:10.1080/10587259508033966

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The relaxation dynamics of nonlinear optical chromophores in photo-polymer composites is studied for a basic understanding of the poling mechanism. The composite films are made up of a photo-polymer containing 0.5 % by weight of 4-dimethylamino-4′-nitrostilbene. They are poled under an external dc electric field at room temperature, followed by UV curing. It is found that for such composite films both the optical retardation and the second harmonic generation (SHG) intensity clearly decay as similar stretched-exponentials in time, and their relaxation behavior is predominantly governed by the period for UV curing. It is suggested that the optical retardation involves mostly the axial order while the SHG intensity is strongly correlated to the degree of polar ordering of the chromophores.

ISSN:1058-725X    

DOI:10.1080/10587259508033967

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We investigate the utilization an organic thin film of a phase II vanadyl phthalocyanine (VOPc), in a new high speed all-optical demultiplexer.

ISSN:1058-725X    

DOI:10.1080/10587259508033968

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

n - Octadecyl 4 - (4′-nitrophenylazo)-1 - naphthyl ether, ONNE, was synthesized and the optical characteristics of ONNE was studied. Noncentrosymmetric Z-type Langmuir-Bodgett (LB) films of ONNE were prepared and the second harmonic generation, SHG, intensity of the films were measured. The structural characteristics of floating monolayer and LB film of ONNE were discussed with the π - A isotherm, UV - visible absorption spectroscopy and ellipsometry. The polarized UV - visible absorption spectroscopy and SHG intensity suggest molecular orientation in LB film.

ISSN:1058-725X    

DOI:10.1080/10587259508033969

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A side chain liquid crystalline polymer was applied to control the alignment of liquid crystal molecules at the interface to the direction of mesogenic side group. The aspects of the alignment were monitored by observing the droplet in the PDLC film. When the composition of the mesogenic side group increases, the configuration of LC droplets changes from bipolar to radial one as designed.

ISSN:1058-725X    

DOI:10.1080/10587259508033970

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Nonlinear optical copolymer with 4-dimethylamino-4′-nitrostilbene as a side chain group was investigated for the photostability by irradiation of infrared light. The light at 1.313 μm, which is very low absorptive for the material, was coupled into the polymeric channel waveguide formed by photobleaching technique. Transmission loss of the infrared light through the channel waveguide has been negeligibly changed even after for a long irradiation. Also, the refractive index change in slab waveguide is undetectable. The nonlinear optical polymer used in this study turns out to be quite reliable in terms of photostability.

ISSN:1058-725X    

DOI:10.1080/10587259508033971

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We synthesized novel side chain copolymers containing the stilbazolium tetraphenylborate for the linear electro-optic coefficient measurement. These polymers are very soluble in common organic solvents such as acetone, cyclohexanone, dimethylformamide etc. The second-order nonlinear optical properties of poly [1-[(N- ethylenepiperazyl)-stilbazolium tetraphenylborate]-N-[(1, l-dimethyl-m-isopropenyl)benzyl]carbamate-co-methylmethacrylate](POLYMER Ia & Ib), poly [l-[(N-ethylenepiperazyl)-stilbazolium tetraphenyl borate]-N-[(1,1-dimethyl-m-isopropenyl)benzyl]carbamate-co-N-vinylcarbazole](POLYMER II), and poly [1-[(N- ethylenepiperazyl)-stilbazolium tetraphenyl borate]-N-[(1, 1-dimethyl-m-Isopropenyl)benzyl]carbamate-co-4-hydroxyphenyl maleimide] (POLYMER III) were improved due to the change of the nonlinear optical chromophore in the side chain.

ISSN:1058-725X    

DOI:10.1080/10587259508033972

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A self-crosslinkable second-order nonlinear optical copolymer with thermal stability at 100°C was prepared by the copolymerization of methacrylic nonlinear optical monomer with glycidyl methacrylate. The nonlinear optical property of this copolymer was compared with that of well-known side-chain polymer P2ANS. Electro-optic coefficient and second harmonic generation measurements showed a r33value of 57 pm/V at 632.8 nm and a d33value of 45.5 pm/V at 1064 nm. Moreover, self-crosslinking during poling was observed between the epoxy groups in the copolymer without adding any crosslinking agent and thus the copolymer showed an excellent thermal stability of aligned chromophores at 100°C. It is thought that the crosslinking was performed between the epoxy groups due to the catalytic basicity of tertiary amine groups in the NLO monomer.

ISSN:1058-725X    

DOI:10.1080/10587259508033973

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor