Role of metal film thickness on the enhanced transmission properties of a periodic array of subwavelength apertures
Role of metal film thickness on the enhanced transmission properties of a periodic array of subwavelength apertures
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DOI：
10.1364/opex.13.009834
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发表时间：
2005-11-28
期刊：
影响因子：
3.8
通讯作者：
Nahata, A
中科院分区：
文献类型：
--
作者：
Shou, X;Agrawal, A;Nahata, A
我们测量了作为金属膜厚度的函数的在薄金属膜中制造的亚波长孔的周期性阵列的增强的透射特性。在这样做时，我们确定的最小金属膜厚度的阵列，表现出共振增强的传输和观察的传输特性的金属膜厚度的增加。探索的厚度范围从delta/15（其中delta是趋肤深度）延伸到大约2 delta。利用太赫兹时域光谱技术，我们测量了透射的宽带太赫兹脉冲的幅度和相位。实验上，我们发现，有一个可以忽略不计的传输增强的金属薄膜作为三角洲/15。随着膜厚的增加，增强效应呈次线性增加，直到膜厚等于趋肤深度。对于金属膜厚超过一个集肤深度，似乎有一点额外的增强在谐振频率。我们还观察到，随着金属膜厚度的增加，有一个相应的增加的谐振频率。(c)2005年美国光学学会
We have measured the enhanced transmission properties of periodic arrays of subwavelength apertures fabricated in thin metal films as a function of the metal film thickness. In doing so, we determine the minimum metal film thickness for an array that exhibits resonantly enhanced transmission and observe the transmission properties as the metal film thickness is increased. The thickness range explored extends from delta/15, where delta is the skin depth, to approximately 2 delta. Using terahertz time-domain spectroscopy, we measure both the amplitude and phase of the transmitted broadband THz pulses. Experimentally, we find that there is negligible transmission enhancement for metal films as thin as delta/15. As the film thickness increases, there is a sublinear increase in the enhancement until the film thickness is equal to the skin depth. For metal films thicker than one skin depth, there appears to be little additional enhancement at the resonant frequencies. We also observe that as the thickness of metal films increases, there is a corresponding increase in the resonance frequencies. (c) 2005 Optical Society of America