光子学报, 2016, 45 (9): 0919001, 网络出版: 2016-10-19
二维三角格光子晶体等效非线性折射率系数研究
Study of Effective Nonlinear Refractive Index Coefficients of Two-dimensional Triangular-lattice Photonic Crystals
非线性效应 等效非线性折射率系数 场平均法 光子晶体 场局域效应 慢光效应 等效折射率 Nonlinear effect Effective nonlinear refractive index coefficient Field averaging method Photonic crystal Local-field effect Slow-light effect Effective refractive index
摘要
考虑光子晶体中场局域效应, 在等效介质理论的基础上利用场平均法得到二维三角格光子晶体的等效折射率.该折射率与平面波展开法得到的结果非常吻合.考虑慢光效应对非线性效应的增强, 引入慢光增强因子得到该光子晶体的等效非线性折射率系数.该光子晶体的等效非线性折射率系数表现出强烈的色散效应, 即随归一化频率的增加而逐渐减小, 达到最小值后迅速递增, 体现了场局域效应和慢光效应对光子晶体中非线性效应的共同作用.本文研究对利用人工微结构调控光学非线性效应具有一定参考价值.
Abstract
Under the condition that the local-field effects in photonic crystals have been considered, a field average method based on the effective medium theory was used to calculate the effective linear refractive index of a two-dimensional triangle-lattice photonic crystal in the first band. The calculated refractive index agrees well with that obtained directly by using the plane-wave expansion method. Furthermore, a slow-light enhancement factor was introduced to calculate the effective nonlinear refractive index coefficients. The calculated nonlinear coefficients of the photonic crystal is strongly dispersive: the nonlinear coefficient decreases slowly to the minimum and then goes up quickly. The frequency-dependent nonlinear coefficients directly demonstrate that the local-field effect and slow light effect influence the nonlinear effects in the photonic crystals simultaneously. The results may be helpful for tuning the nonlinear effects by using man-made microstructures.
周科涛, 唐志祥, 易为, 潘蓉, 潘进, 周政. 二维三角格光子晶体等效非线性折射率系数研究[J]. 光子学报, 2016, 45(9): 0919001. ZHOU Ke-tao, TANG Zhi-xiang, YI Wei, PAN Rong, PAN Jin, ZHOU Zheng. Study of Effective Nonlinear Refractive Index Coefficients of Two-dimensional Triangular-lattice Photonic Crystals[J]. ACTA PHOTONICA SINICA, 2016, 45(9): 0919001.