Author Affiliations
Abstract
Department of Electronic Engineering, School of Information Science and Engineering, Xiamen University, Xiamen 361005, China
We demonstrate a soft lithography approach for fabrication of a topographically patterned polyvinyl alcohol (PVA) liquid-crystal (LC) alignment layer. This specific approach employs modified micromolding in capillaries for negative replication of the PVA microstructures on indium tin oxide (ITO) substrates from patterned poly(dimethylsiloxane) molds in a single step, leading to planar alignment on the desired regions. By doping with polyhedral oligomeric silsesquioxane nanoparticles, which can induce vertical alignment on bare ITO surfaces, periodic LC phase gratings based on an alternating vertical-aligned/hybrid-aligned nematic geometry are presented as an application, and a theoretical model was used to simulate and examine the experimental results.
160.3710 Liquid crystals 160.4670 Optical materials 160.5470 Polymers 050.1950 Diffraction gratings Chinese Optics Letters
2015, 13(8): 081603
Author Affiliations
Abstract
Department of Electronic Engineering, Xiamen University, Xiamen 361005, China
We examine the temperature-dependent reflection shifts, microscopic morphology, and laser emission of polymer-stabilized cholesteric liquid crystals. The preparation parameters, including the concentration of photo-initiator and laser dye, are evaluated and their influence on reflection band is considered not to be ignorable. Inadequate ultraviolet (UV) curing time less than the required value to fully photo-polymerize the monomer can also influence the spectral position and shape of the reflection band but still favor possible band-edge lasing, whereas extending UV curing duration can weaken and eventually eliminate the laser emis-sion. The behaviors are explained using the results derived from the mean field theory.
160.3710 Liquid crystals 140.2050 Dye lasers 160.3380 Laser materials Chinese Optics Letters
2014, 12(11): 111602
Author Affiliations
Abstract
We report the fabrication and optical characterization of spherical whispering gallery mode (WGM) resonators made from ultraviolet (UV)-curable adhesive. The fabricated microspheres have good sphericity and surface smoothness, and can directly adhere to the tip of half-tapered fibers for easy manipulation. WGMs are efficiently excited in the microsphere using an evanescent field of the tapered silica optical fibers. Resonances with quality factors of 1.3 \times 105 are observed. The dependence of wavelength shifts of WGM resonances on the input light powers shows that the resonant wavelength of the proposed microsphere resonators can be tuned thermo-optically.
140.4780 Optical resonators 160.6840 Thermo-optical materials 230.4000 Microstructure fabrication 260.5740 Resonance Chinese Optics Letters
2013, 11(10): 101401
Author Affiliations
Abstract
A two-dimensional (2D) distributed feedback (DFB) structure is fabricated on dye-doped sol-gel derived hybrid zirconia films by soft lithography. The Q-switched Nd:YAG laser (\lambda = 532 nm) is used to pump these structures. The lasing emissions of the gain medium doped with Rhodamine 6G (Rh6G) in two perpendicular directions are shown, and the threshold pump energy is measured.
140.2050 Dye lasers 050.2770 Gratings 310.6845 Thin film devices and applications Chinese Optics Letters
2012, 10(5): 051401
阐述了一种在掺锆杂化薄膜上获得分布反馈结构的软刻蚀制备方法，该薄膜采用可紫外光交联的溶胶凝胶(sol-gel)法制得。采用全息双光束干涉方法制备一维光栅母版，并将聚二甲基硅氧烷(PDMS)预聚物浇铸在光栅母版上，加热固化后发生交联反应可以得到弹性体印章。采用旋转涂覆的方法在玻璃基片上制备掺锆的杂化薄膜后，并将弹性体印章覆盖在掺锆的杂化薄膜上，再分别经过预热处理、紫外光照和后热处理，揭起后即可在薄膜上获得分布反馈式结构。使用原子力显微镜(AFM)和扫描电镜(SEM)分别对光栅母版，PDMS印章以及复制获得的掺锆的溶胶凝胶上的分布反馈结构进行了分析研究，研究发现光栅母版的微结构成功复制到掺锆的溶胶凝胶薄膜的表面，并具有相同的周期结构。
掺锆杂化薄膜 分布反馈 软刻蚀技术 聚二甲基硅氧烷
1 厦门大学电子工程系, 福建 厦门 361005
2 浙江大学材料系, 浙江 杭州 310027
成功引入芳胺基给体,使用溶胶-凝胶(sol-gel)技术制备出键连型杂化薄膜(F-TPA),并用原子力显微镜(AFM)研究了F-TPA极化前后的表面形貌。原位光学二次谐波测量表明,此类芳胺基给体型二阶非线性光学杂化薄膜具有良好的非线性光学性能(d33为14.1 pm/V)和较高的取向热稳定性(d33值在115 ℃仍然能保持稳定,半衰温度达到145℃左右)。结果接近实用要求,充分显示了其在器件实用化进程中的优势。ITO玻璃表面薄膜样品的极化效果远优于普通玻璃片表面的样品。在不使用平面栅网、单针极化的情况下,仍然能在ITO玻璃表面的薄膜获得均匀、饱和的d33分布。
非线性光学 芳胺给体 溶胶-凝胶 极化
