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在可见光波段(λ=750nm),实验研究了在端面辅助情况下,细纳米银线波导中表面等离极化波激发和辐射的偏振特性.实验发现在细纳米银线中,不同偏振态的入射光对应的表面等离极化激元的激发和传输效率有明显不同,但对应的出射光始终为方向恒定的线偏振光.对于化学合成的纳米银线,端面的轴对称性普遍比较好,对此类纳米银线进行激发时,如果入射光偏振态与纳米线近似平行,则激发和传输表面等离极化激元的效率最高;如果正交,激发和传输效率则最低.对于某些端面轴对称性较差的纳米银线,如端面为尖端或类斜面,当入射光偏振态与纳米线有一定夹角时,激发和传输表面等离极化激元的效率最高.在入射光偏振改变的过程中出射光的偏振方向始终与纳米银线平行.最后结合有限元差分方法理论解释了纳米银线中这种偏振特性的物理机理.利用纳米银线中表面等离极化激元激发和辐射的偏振特性,可以在亚波长尺寸上实现对光强和偏振态的调控.
In the visible light band (λ = 750nm), the polarization characteristics of the surface plasmon polariton excitation and radiation in a fine nanosilver waveguide were investigated experimentally with the aid of an end face. The experimental results show that in the fine nanosilver wires, The excitation and transmission efficiencies of the surface plasmon polaritons corresponding to the incident light are obviously different, but the corresponding emergent light is always the linearly polarized light of constant direction. The axial symmetry of the end surface is generally better for the chemically synthesized nanosilver wire , The excitation and transmission of surface plasmon polaritons are most efficient when the polarization state of the incident light is parallel to the nanowires when excited by such nanosilver lines and the lowest is the excitation and transmission efficiency if orthogonal The nanosilver wires with poor axial symmetry at the end face, such as the tip or bevel, have the highest efficiency of excitation and transport of the surface plasmon polaritons when the polarization state of the incident light is at an angle with the nanowires. The polarization direction of the outgoing light is always parallel to the nanowire silver line during the change of light polarization.Finally, the physical mechanism of this polarization characteristic in the nanowire silver line is explained by the theory of finite difference method.Using the surface of the nanowire silver line Polarization characteristics and the excitation radiation plasmon polariton can be achieved regulatory light intensity and polarization state of the sub-wavelength in dimension.