Study on absorption enhancement of sub-wavelength metal groove array
In this paper,the absorption enhancement of sub-wavelength metal groove array is systematically studied by rigorous numerical analysis.According to the characteristics of single-layer and double-layer rectangular groove arrays,the effects of structural parameters and metal type on absorption efficiency of the array are numerically simulated.The study results show that the absorption enhancement of the sub-wavelength metal groove array mainly comes from the local mode resonance in grooves.Large absorption efficiency for narrow grooves with strong resonance can be obtained.Compared with a single-layer groove array,the absorption enhancement of double-layer groove array mainly depends on the upper-layer-width under resonance condition,and weekly depends on the lower-layer width which deeply affects the resonance depth for lower layer grooves.Results of double-layer groove array in this paper provide numerical simulation references for the algorithm in further studying of absorption enhancement by V-shaped grooves,trapezoidal grooves and so on,which can obtain giant absorption enhancement with lower fabrication difficulty.Our study can also provide important parameter guidance for the device design with the sub-wavelength groove array in metallic substrate as the absorption enhancement unit.
rigorous coupled wave analysissub-wavelength metal rectangular groove arrayFabry-Perot resonanceabsorption enhancement
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