單狹縫之漏斗效應為影響單狹縫穿透率之重要因素之一。先前之研究中，對單狹縫穿透率隨狹縫厚度與寬度變化之現象已有相當之了解[10]。但對漏斗效應細部特性之瞭解卻仍然有不足之處。因此，本研究探討了漏斗效應的能量流動，並以此定義了漏斗形狀。在不包含Fabry-Pérot共振現象的情況下，次波長狹縫的寬度越小，穿透率越大，而我們發現隨著寬度越小則漏斗也會越大，即漏斗形狀與穿透率有一致之變化。進一步我們發現漏斗之邊界為金屬表面上 與 相位差為 之位置。狹縫寬度減小，邊緣處的相位差減小，漏斗內的平均相位差斜率降低，導致了漏斗形狀持續增大。
包含Fabry-Pérot共振現象時，我們也發現漏斗形狀與穿透率之變化一致。在固定狹縫寬度下，最大之穿透率膜厚之漏斗形狀會大於穿透率最小膜厚之漏斗形狀。這是因為狹縫邊緣處的 與 之相位差會隨膜厚變化。另一方面，我們觀察了狹縫內之反射波對漏斗之影響。最小穿透率之膜厚下，漏斗形狀將隨時間縮小，故有較小之漏斗形狀，而穿透率最大之膜厚則幾乎保持不變。固定狹縫厚度下，穿透率與漏斗之變化也有一致之現象。本研究由漏斗形狀之分析進一步理解漏斗效應之基本性質，應能增進我們對單狹縫穿透機制的理解。

The funneling effect of single slit is one of the important factors for transmittance. From previous study, we already have a general understanding about the variation of transmittance with slit width and film thickness. However, there is no further understanding on the details of the characteristics of the funneling effect. In this study, we observe the energy flow distribution of funneling effect and use it to define the shape of funnel. Without the influence of Fabry-Pérot resonance, transmittance is increased and the funnel shape grows bigger with smaller slit width. Next, we observe the phase distribution of and on the metal surface. We find that the boundary of funnel lies at the position where the phase difference between and is . Furthermore, the phase difference at the slit edge and the average phase difference slope decreases with smaller slit width. Thus the funnel shape is bigger for smaller slit width. When including Fabry-Pérot resonance, we also found that the funnel shape grows bigger with lager transmittance. For fixed slit width, the funnel shape of maximum transmittance is larger than that of minimum transmittance. This is also the result of the phase difference at the slit edge and the average phase difference slope. The Reflection wave in the slit makes the funnel smaller for minimum transmittance and does not change the funnel much for maximum transmittance. For fixed film thickness, similar variation is also observed. This study further investigate the fundamental properties of funneling effect through the shape of funnel and it should give us a better understanding of the mechanism in the transmission of single slit.

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