提出了一种有双谐振频率和较宽谐振区域的纳米天线结构.利用有限积分法,计算了由金构成的表面等离子体光学纳米天线的谐振特性,研究了在谐振区域内谐振频率和谐振电场随位置变化的情况.结果表明,在不同谐振频率下存在两个谐振电场,在中间区域,谐振频率为270 THz,在侧边间隙区,谐振频率为390 THz;激励源为1 V/m时,其谐振电场均达700 V/m以上,是普通偶极子天线的18倍;第一谐振区域的谐振场集中在10～25 nm,在此范围内,谐振电场较大、谐振频率几乎不变;加上折射率为1.5的玻璃衬底后,天线的谐振电场达到800 V/m,与没有衬底时相比,谐振频率变化很小.研究的天线结构在高性能的光学纳米天线、太阳能电池和生物传感器方面有潜在的应用价值.%A nano-antenna with two resonant frequencies and wider resonant areas was constructed.On the basis of the finite integral method,the resonant properties of the surface plasmon optical nano-antenna constructed by Au were calculated and the resonant frequencies and resonant fields in resonant areas were mainly simulated.The experiments show that there are two resonant areas in different resonant frequencies,which are 270 THz at the middle gap and 390 THz at the side gap.Their resonant electric fields are up to 700 V/m,which is about 18 times higher than that of the common dipole antenna when the excitation field is 1 V/m.The resonance field at the first resonant area is confined at the central part from 10 nm to 25 nm along the Z-axis direction,the resonant frequency is almost not changed and the magnitude is greater.The structure with a glass substrate of refraction index of 1.5 is also considered,the resonant field is up to 800 V/m,whereas the resonant center frequencies are almost not changed.The proposed structure has potential applications to high-quality optical antennas,solar cells,and biosensors.
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