共查询到14条相似文献,搜索用时 156 毫秒
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由实验测量得到的不同写入角度下的衍射效率,通过衍射效率与折射率对比度的关系,间接得到了折射率对比度与光子晶格周期的关系.关系表明折射率对比度随晶格周期的变化确实有一极值存在.说明写入不同周期的光子晶格会有不同的折射率对比度.用不同掺铁浓度的晶体实验时发现随着掺铁浓度的增大折射率对比度的最大值也增大,并且最大值的位置向晶格周期人小的方向移动,这与理论计算结果相吻合.因此,在实验与理论上证实了折射率对比度确实与写入的光子晶格的周期和掺铁浓度有关. 相似文献
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从双光束耦合实验入手,在非同时读出条件下测量LiNbO3∶Fe晶体两波耦合过程中,不同写入角度(光子晶格周期)、不同的读写条件下,衍射效率随时间的变化。结果表明衍射效率随时间出现振荡变化。用小周期写入时,不容易出现振荡。同时用o光写入e光读出时,得到的光子晶格稳定且衍射效率较高。另外从理论上定性分析了衍射效率随时间的振荡变化。认为这是由空间二次谐波和动态能量转移及瞬态条纹位错引起的。通过实验与理论上的分析,得出光子晶格的最佳写入时间为第一个峰值出现所对应的时间。 相似文献
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Zhaoting Liu Soshu Kirihara Yoshinari Miyamoto Di Zhang 《Journal of the American Ceramic Society》2006,89(8):2492-2495
Three-dimensional photonic crystals were fabricated by infiltrating an epoxy mold with a SiC/polyester mixture. The epoxy molds with normal or inverse diamond structures were formed by stereolithography. The size of the mold was 45 mm × 18 mm × 18mm, and the lattice constant of the photonic crystals was 18 mm. The effects of the epoxy mold type, aspect ratio (the ratio of height and diameter of a diamond lattice rod), and number of sample units on the formation of photonic band gap (PBG) and microwave absorption ability along the 〈100〉 direction were studied. The attenuations of microwave transmission and reflection were measured through the photonic crystal samples at a frequency range of 3–12 GHz with a network analyzer. The results obtained suggest that the combination of the absorbing material SiC and diamond structure has a dual effect to form a PBG with a high absorption ability. 相似文献