Modeling infrared radiative properties of nanoscale metallic complex slit arrays
来源期刊：中南大学学报(英文版)2014年第10期
论文作者：WANG Ai-hua(王爱华) NIU Yi-hong(牛义红) CHEN Yu-bin(陈玉彬)
文章页码：3927 - 3935
Key words：finite difference time domain method; subwavelength structures; radiative properties; complex slit arrays; cavity resonance
Abstract: The radiative properties (absorptance, reflectance, and transmittance) of deep slits with five nanoscale slit profile variations at the transverse magnetic wave incidence were numerically investigated by employing the finite difference time domain method. For slits with attached features, their radiative properties can be much different due to the modified cavity geometry and dangled structures, even at wavelengths between 3 and 15 μm. The shifts of cavity resonance excitation result in higher transmittance through narrower slits at specific wavelengths and resonance modes are confirmed with the electromagnetic fields. Opposite roles possibly played by features in increasing or decreasing absorptance are determined by the feature position and demonstrated by Poynting vectors. Correlations among all properties of a representative slit array and the slit density are also comprehensively studied. When multiple slit types coexist in an array (complex slits), a wide-band transmittance or absorptance enhancement is feasible by merging spectral peaks contributed from each type of slits distinctively. Discrepancy among infrared properties of four selected slit combinations is explained while effects of slit density are also discussed.
WANG Ai-hua(王爱华)1, NIU Yi-hong(牛义红)1, CHEN Yu-bin(陈玉彬)2
(1. School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China;
2. Department of Mechanical Engineering, National Cheng Kung University, Tainnan 701, China)
Abstract:The radiative properties (absorptance, reflectance, and transmittance) of deep slits with five nanoscale slit profile variations at the transverse magnetic wave incidence were numerically investigated by employing the finite difference time domain method. For slits with attached features, their radiative properties can be much different due to the modified cavity geometry and dangled structures, even at wavelengths between 3 and 15 μm. The shifts of cavity resonance excitation result in higher transmittance through narrower slits at specific wavelengths and resonance modes are confirmed with the electromagnetic fields. Opposite roles possibly played by features in increasing or decreasing absorptance are determined by the feature position and demonstrated by Poynting vectors. Correlations among all properties of a representative slit array and the slit density are also comprehensively studied. When multiple slit types coexist in an array (complex slits), a wide-band transmittance or absorptance enhancement is feasible by merging spectral peaks contributed from each type of slits distinctively. Discrepancy among infrared properties of four selected slit combinations is explained while effects of slit density are also discussed.
Key words:finite difference time domain method; subwavelength structures; radiative properties; complex slit arrays; cavity resonance
