Arizona Center for Mathematical Sciences, University of Arizona, Tucson, Arizona 85721, USA.
Opt Lett. 2009 Sep 15;34(18):2844-6. doi: 10.1364/OL.34.002844.
We analytically study second-harmonic (SH) generation from thin metallic films with subwavelength noncentrosymmetric patterns. Because the thickness of the film is much smaller than the SH wavelength, retardation effects are negligible. The far-field SH intensities are thus dominated by an effective electric dipole. It is further demonstrated that internal bulk SH polarization density is comparable with its surface counterpart. The electric dipole, consequently, originates from the entire volume of the metallic membrane.
我们分析研究了亚波长非中心对称图案的薄金属膜中的二次谐波（SH）产生。由于膜的厚度远小于 SH 波长，因此可以忽略延迟效应。因此，远场 SH 强度主要由有效电偶极子主导。进一步证明，内部体 SH 极化密度与其表面对应物相当。因此，电偶极子源于整个金属膜的体积。
