采用镂空模板法制备了大面积周期孔状金属薄膜,实验揭示了金属小孔阵列在中红外波段的异常透过率增强现象。通过对周期孔状金属薄膜处于不同周围介质下得到的透射谱的研究发现,透射峰随着周围介质折射率的增大会有很明显的红移。比较周期孔状金属薄膜传感器非对称结构和对称结构的灵敏度发现,其对称结构下的灵敏度要高于非对称结构下的灵敏度。通过改变金属薄膜的一些参数,得到金属薄膜厚度和基底折射率为100 nm和1.3时灵敏度最大,分别为12 383 nm/RIU(refractive index unit)和12 667 nm/RIU;灵敏度随周期性孔径的增大而增大;孔的形状与圆的差别越大,灵敏度越高;灵敏度随孔中介质折射率的减小而增大。
The stencil mask method is used to fabricate large-scale metal films perforated with periodic hole arrays,and the enhanced transmission through metal films perforated with periodic hole arrays is explored experimentally in the middle infrared wavelength.By studying the transmission spectra of metal films perforated with periodic hole arrays surrounded by different mediums,we find that transmission spectra show redshifts with the increasing of medium′s refractive index.By comparing the sensitivity of perforated metal films with asymmetrical and symmetrical structures,it is found that the sensitivity of the symmetrical structure is better than that of the asymmetrical structure.By changing some parameters of metal films,we find that metal films with the thickness of 100 nm and substrate with the refractive index of 1.3 have the maxima sensitivities(12 383 nm/RIU and 12 667 nm/RIU).Moreover,the sensitivity can be further increased by the increase of periodic aperture′s diameter,the shape difference of apertures from circle,and the decrease of the refractive index in apertures.