亚波长分形结构太赫兹透射增强的机理研究

Study of enhanced transmission of terahertz radiation through subwavelength fractals structures

利用太赫兹时域光谱(terahertz time domain spectroscopy,简称THz-TDS),研究了亚波长金属分形结构在THz波段的透射增强特性.分别从实验和理论两个方面,研究了铜箔上各级分形结构THz透射增强现象的产生机理.结果表明,在低频区的透射增强主要是由低级分形线中电子运动的共振引起的,而高频区的透射增强则主要由高级分形线中电子运动的共振引起的.从而将这种透射增强效应归结为分形结构中电子的共振辐射,即分形结构的局域共振效应.

The enhanced transmission of terahertzs radiation through the metal subwavelength fractal structures is studied by means of the terahertz time domain spectroscopy （THz-TDS）. In view of experiment and theory, the physical mechanism of enhanced transmission of THz wave through each level of fractal lines on the copper film is studied. It is found that THz transmission enhancement in low frequency region mainly resulted from the electron resonance in low level lines, and that in high frequecy region mainly resulted from the electron resonance in high level lines. Thus the transmission enhancement can be attributed to the electron resonant radiation in the fractal structure, namely,the localized resonance efficiency of the frqctal structure.