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用真空镀膜方法制备了含有单个CdS缺陷层的具有不同周期和结构参量的TiO2/SiO2一维光子晶体。用抽运探测技术研究了CdS缺陷层的双光子吸收(TPA)现象。实验结果表明:一维光子晶体中CdS缺陷层的双光子吸收显著增强。不同周期和结构参量的一维光子晶体中CdS缺陷层的双光子吸收系数不同。双光子吸收的增强来源于由光局域化导致的缺陷层的电场强度的增加。缺陷层电场强度与一维光子晶体的结构有关,如周期,光子带隙的位置与宽度及缺陷模式等因素都会影响缺陷层电场强度。采用四分之一波长的高低折射率介质层和与入射波长匹配的缺陷模可以得到最大的缺陷层电场强度。
A one-dimensional photonic crystal of TiO2 / SiO2 with different period and structure parameters containing a single CdS defect layer was prepared by vacuum deposition. Two-photon absorption (TPA) phenomenon of CdS-deficient layer was studied by the pump detection technique. The experimental results show that the two-photon absorption of CdS-deficient layer in one-dimensional photonic crystal is significantly enhanced. The two-photon absorption coefficients of CdS-deficient layers in one-dimensional photonic crystals with different periods and structural parameters are different. The enhancement of two-photon absorption is due to an increase in the electric field strength of the defect layer caused by optical localization. The electric field strength of the defect layer is related to the structure of the one-dimensional photonic crystal. For example, the period, the position and width of the photonic band gap and the defect mode all affect the electric field strength of the defect layer. The maximum defect layer electric field intensity can be obtained by using a quarter-wavelength high and low index dielectric layer and a defect mode matching the incident wavelength.