椭圆金环结构的太赫兹透射增强

Transmission Enhancement of Terahertz Radiation Through the Ellipse Gold Rings Structure

利用太赫兹时域光谱系统,测量了3种在硅衬底上淀积厚度为100nm金膜的椭圆环阵列结构后,并且分析了各样品在太赫兹波段的透射增强现象及产生机理.结果表明:在整个太赫兹波段,此组结构样品的透射系数均在0.68以上,产生明显的透射增强;当太赫兹波的偏振方向与椭圆环长轴之间的夹角为90°时,3个样品在1.67THz处的共振峰是由于短轴方向的电子形成偶极子振荡与入射太赫兹波进行耦合产生的;夹角为0°时,周期阵列样品无明显共振峰,而分形阵列样品的共振峰则不如斑图阵列样品的明显;样品结构的对称性越差,透射谱的信息越丰富.此外,分析相位差谱也验证了共振增强透射的存在.

The terahertz time domain spectroscopy technology is used to measure the terahertz spectral of three ellipse gold rings structure which deposited on the silicon substrate by the photo lithography technique and the thickness of gold film are about 100 nm. Then the physical mechanism of transmission enhancement through the structures is analyzed. The results show that the transmission coefficients of these structure samples are above 0. 7 which suggests the sharp transmission enhancement in THz wave band. When the angle between the THz wave polarization direction and the long axis of elliptic ring is 90°, the resonance peak at 1.67 THz is result from the coupling between the short axis direction of electronic formed dipole oscillation and the incident THz wave. While the angle is 0°, the periodic array sample has not obvious resonance peak, the resonance peak of the patter array sample is obviously than the fractal array sample, the worse symmetry of the samples＇ structure, the richer information of the transmission spectra. Moreover, the phase differences spectrums are also verify the existence of resonance enhanced transmission.