Do Danh Bich, Lin Jian Hung, Lai Ngoc Diep, Kan Hung-Chih, Hsu Chia Chen
Department of Physics, National Chung Cheng University, Ming Hsiung, Chiayi, Taiwan.
Appl Opt. 2011 Aug 10;50(23):4664-70. doi: 10.1364/AO.50.004664.
We demonstrate the fabrication of a three-dimensional (3D) polymer quadratic nonlinear (χ(2)) grating structure. By performing layer-by-layer direct laser writing (DLW) and spin-coating approaches, desired photobleached grating patterns were embedded in the guest-host dispersed-red-1/poly(methylmethacrylate) (DR1/PMMA) active layers of an active-passive alternative multilayer structure through photobleaching of DR1 molecules. Polyvinyl-alcohol and SU8 thin films were deposited between DR1/PMMA layers serving as a passive layer to separate DR1/PMMA active layers. After applying the corona electric field poling to the multilayer structure, nonbleached DR1 molecules in the active layers formed polar distribution, and a 3D χ(2) grating structure was obtained. The χ(2) grating structures at different DR1/PMMA nonlinear layers were mapped by laser scanning second harmonic (SH) microscopy, and no cross talk was observed between SH images obtained from neighboring nonlinear layers. The layer-by-layer DLW technique is favorable to fabricating hierarchical 3D polymer nonlinear structures for optoelectronic applications with flexible structural design.
我们展示了一种三维（3D）聚合物二次非线性（χ(2)）光栅结构的制备方法。通过逐层直接激光写入（DLW）和旋涂方法，通过对分散红-1/聚甲基丙烯酸甲酯（DR1/PMMA）分子进行光漂白，将所需的光漂白光栅图案嵌入到有源-无源交替多层结构的客体-主体DR1/PMMA有源层中。聚乙烯醇和SU8薄膜沉积在DR1/PMMA层之间，作为隔离DR1/PMMA有源层的无源层。对多层结构施加电晕电场极化后，有源层中未漂白的DR1分子形成极性分布，从而获得了三维χ(2)光栅结构。通过激光扫描二次谐波（SH）显微镜对不同DR1/PMMA非线性层的χ(2)光栅结构进行了成像，相邻非线性层获得的SH图像之间未观察到串扰。逐层DLW技术有利于制造具有灵活结构设计的用于光电子应用的分层三维聚合物非线性结构。
