Analysis and control of heat transfer in laser induced thermal poling process of polymer thin film

聚合物薄膜激光诱导热极化过程传热分析与控制

• 批准号: 09450283
• 负责人: HOZAWA Mitsunori
• 金额: $ 3.07万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450283/
• 关键词: Nonlinear optical material; Polymer thin film; Laser induced thermal poling; Heat transfer; Thermal diffusivity; Dipole orientation; Numerical simulation; 非線形光学材料; 非線形工学材料; レーザー加熱ボーリング

We have focused on the development and the optimization of waveguide patterning process in nonlinear optical (NLO) polymer thin film by laser induced thermal poling. In this research, we have elucidated the following subjects.1) Measurement of the thermal diffusivity of NLO polymer thin film.Thermal properties of NW polymer are an important factor in the thermal poling process. To measure the thermal diffusivity of the nonlinear optical (NW) polymer thin film, we modified the experimental apparatus based on the photoacoustic method. PMMA with DR1 chromosphore side groups was synthesized as an NLO polymer. It was found that the thermal diffusivity is independent on film thickness and percentage of the chromosphore, but increases as the applied electric field increases. Also, the thermal diffusivity of the NLO polymer thin film decreases with temperature. Our apparatus has no capability to measure at high temperature, more than glass transition temperature (about 380K) which gives abrupt … More ly change in thermal diffusivity, It is desired to develop another method to measure thermal diffusivity at high temperature.2) Numerical simulation of laser induced thermal poling processWe have constructed three-dimensional simulation code to estimate temperature profile in NW polymer thin) film on thermal poling process. To elucidate optimized condition for uniform polarization profiles, we introduced the temperature dependence of dipole (in NLO molecule) orientation dynamics to our simulation code. Since there is no available model for dipole orientation dynamics, relaxation dynamics model was used. At first, Ar^+ laser (wavelength of 488 nm) was used as light source on simulation. The calculation results showed that smaller diameter of laser beam and slower scanning speed of laser give more uniform polarization profiles. Since absorption spectrum of thin film suggests that He-Ne laser (wavelength of 632 nm) illuminates the thin film more interior than Ar^+ laser, He-Ne laser results in higher and more uniform polarization profiles. It is necessary to measure the dipole orientation dynamics for polymer materials in an electric field. Less

我们专注于通过激光诱导热极化在非线性光学（NLO）聚合物薄膜中进行波导图案化工艺的开发和优化。在这项研究中，我们阐明了以下主题：1）NLO聚合物薄膜热扩散率的测量。纳米线聚合物的热性能是热极化过程中的一个重要因素。为了测量非线性光学（纳米线）聚合物薄膜的热扩散率，我们改进了基于光声方法的实验装置。具有 DR1 发色团侧基的 PMMA 被合成为 NLO 聚合物，发现热扩散率与膜厚度和发色团百分比无关，但随着施加的电场的增加而增加。此外，NLO 聚合物薄的热扩散率也增加。薄膜随温度降低。我们的设备无法在超过玻璃化转变温度（约 380K）的高温下进行测量，这会导致热扩散率突然变化，因此需要开发另一种2）激光诱导热极化过程的数值模拟我们构建了三维模拟代码来估计热极化过程中纳米线聚合物薄膜的温度分布，以阐明均匀偏振分布的优化条件。我们在模拟代码中引入了偶极子（NLO 分子）取向动力学的温度依赖性，因为没有可用的偶极子取向动力学模型，因此首先使用 Ar^+ 激光（波长为 488）。 nm）作为光源进行模拟，计算结果表明，由于薄膜的吸收光谱表明He-Ne激光（波长为632 nm），较小的激光束直径和较慢的激光扫描速度会产生更均匀的偏振轮廓。与 Ar^+ 激光相比，He-Ne 激光照射的薄膜更内部，因此有必要测量电场中聚合物材料的偶极子取向动力学。