Tsutsumi Naoto, Kaida Keiichi, Kinashi Kenji, Sakai Wataru
Faculty of Materials Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto, 606-8585, Japan.
Master's Program of Innovative Materials, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto, 606-8585, Japan.
Sci Rep. 2019 Jul 22;9(1):10582. doi: 10.1038/s41598-019-47098-4.
Organic solid-state lasers (OSSLs) with distributed feedback (DFB) structures or distributed Bragg reflectors (DBRs) are promising for potential application in bio-sensing and hazardous materials detection. Here, the laser performances of the all-organic DFB waveguide lasers with various grating heights ranging from 0.4 to 4.7 μm were investigated. The grating structures used as the lasing cavity were fabricated using a two-photon absorption (TPA) direct laser writing (DLW) method with an SU-8 negative photoresist. The laser active layer consisted of a rhodamine 6G (R6G) laser dye and a cellulose acetate (CA) matrix. The R6G/CA solution was spin-coated onto the quartz substrate with the cavity (grating) structures to fabricate the DFB waveguide laser devices. The diffraction order of lasing ranged from m = 4 to 7. As the grating height was increased to 1.9 μm, the slope efficiency increased for all diffraction orders and the threshold decreases for each diffraction order. The dependence of the cavity (grating) length on the laser performances was investigated. The slope efficiency increased as the cavity length increased to 300 μm. The effect of the cavity (grating) position on the slope efficiency and the threshold position of the cavity (grating) was also studied. A maximum slope efficiency of 10.2% was achieved for the DFB waveguide laser device with a cavity (grating) length of 300 μm, a cavity position at 6 mm from the emission edge of the waveguide, and an aspect ratio ≈3 between the grating height of 1.74 μm and the grating width of 0.6 μm for the diffraction order m = 6 for lasing.
具有分布反馈（DFB）结构或分布布拉格反射器（DBR）的有机固态激光器（OSSL）在生物传感和有害物质检测方面具有潜在的应用前景。在此，研究了具有0.4至4.7μm不同光栅高度的全有机DFB波导激光器的激光性能。用作激光腔的光栅结构是使用双光子吸收（TPA）直接激光写入（DLW）方法和SU-8负性光刻胶制造的。激光活性层由罗丹明6G（R6G）激光染料和醋酸纤维素（CA）基质组成。将R6G/CA溶液旋涂到具有腔（光栅）结构的石英衬底上，以制造DFB波导激光器件。激光的衍射级范围为m = 4至7。随着光栅高度增加到1.9μm，所有衍射级的斜率效率均增加，且每个衍射级的阈值降低。研究了腔（光栅）长度对激光性能的依赖性。随着腔长度增加到300μm，斜率效率增加。还研究了腔（光栅）位置对斜率效率和腔（光栅）阈值位置的影响。对于衍射级m = 6的激光，腔（光栅）长度为300μm、腔位置距波导发射边缘6mm且光栅高度为1.74μm与光栅宽度为0.6μm的纵横比≈3的DFB波导激光器件实现了10.2%的最大斜率效率。
