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分析了一维金属-介质周期结构的能带特性,根据一定频率范围内TM波(磁场方向与界面平行)在结构中的负折射以及TE波的正常折射,提出了一种偏振分束器件。利用传输矩阵法(TMM)模拟了该结构对入射高斯光束的偏振分束作用,讨论了不同入射角度下的偏振分束能力,并结合实际金属参量,分析了金属层吸收对结构特性的影响。结果表明该结构在55°附近入射时有最好的性能;在吸收作用下结构偏振分束能力有一定的减小,TM波透射比发生了较大变化,TE波效果较好;随着周期数增加,结构透射比下降,但分光能力显著提高;在工作波段上随着波长增大,金属层吸收对器件的影响减弱。该结构能实现宽波段、宽角度、较高透射比的偏振分束。
The energy band characteristics of one-dimensional metal-dielectric periodic structure are analyzed. According to the negative refraction of the TM wave (the direction of the magnetic field is parallel to the interface) in the structure and the normal refraction of the TE wave in a certain frequency range, a polarization beam splitting device is proposed. The polarization beam splitting effect of the structure on the incident Gaussian beam was simulated by transmission matrix method (TMM). The polarization beam splitting capability under different incident angles was discussed. The effect of metal layer absorption on the structural properties was also analyzed with the actual metal parameters. The results show that the structure has the best performance when it enters near 55 °. The polarization splitting ability of the structure decreases to a certain degree under the action of absorption, the TM transmittance has a great change, and the TE wave works well. With the period The transmittance of the structure is decreased, but the optical splitting capability is significantly improved. With the increase of the wavelength in the working wavelength band, the influence of the metal layer absorption on the device is weakened. The structure can achieve broadband, wide angle, high transmittance of the polarization beam splitter.