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研究了波状结构二维光子晶体(2DPC)在红外波段的负折射近场成像,对其等频面进行了分析,指出波状结构二维光子晶体无法实现负折射远场成像的原因在于缺少与入射介质等频面相匹配的光子晶体圆形等频面,所用的矩形等频面使波状膜层二维光子晶体不可避免地具有各向异性特征,进而将成像限制在近场范围内。采用时域有限差分(时域有限差分)方法模拟了不同厚度的波状结构二维光子晶体近场成像效果,当厚度为两倍栅格常量时,单光源的成像分辨力为0.28λ,达到亚波长分辨效果。分辨力随着光源逐渐远离近场范围而降低,而像点的位置基本不随光源距离和光子晶体厚度的变化而改变。双光源的成像模拟进一步验证了波状结构二维光子晶体的近场亚波长成像能力,分辨力达到0.35λ,但成像质量受光子晶体厚度变化的影响较大。
The negative refractive near-field (2D) imaging of two-dimensional (2DPC) wave-like structures in the infrared region was studied. The isoconvex surface was analyzed. The reason why the two-dimensional photonic crystals with corrugated structure can not realize negative- Media and other frequency-matched photonic crystals such as the circular surface of the frequency, such as the use of the rectangular wave-shaped photonic crystal two-dimensional photonic crystals inevitably have anisotropic characteristics, and then the imaging limit in the near-field range. The time-domain finite difference (FDTD) method was used to simulate the effect of near-field imaging of two-dimensional photonic crystals with different thickness. When the thickness was twice grid constant, the resolution of the single light source was 0.28λ, Wavelength resolution effect. The resolution decreases as the light source gradually moves away from the near field and the position of the image point does not substantially change with the distance of the light source and the thickness of the photonic crystal. The imaging simulation of the double light source further validates the near-field subwavelength imaging capability of the wavy two-dimensional photonic crystal with a resolution of 0.35λ, but the imaging quality is greatly affected by the photonic crystal thickness variation.