Department of Electronics and Applied Physics, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuta, Yokohama 226-8502, Japan.
Opt Lett. 2012 Oct 1;37(19):4053-5. doi: 10.1364/OL.37.004053.
Electromagnetic wave emission based on optical rectification at terahertz (THz) wavelengths was observed from surface-immobilized gold nanospheres (SIGNs) above a gold surface. Although the excitation wavelength is off-resonant with the localized surface plasmons, the THz emission field was observed to be approximately 4.8 times greater than that from a percolated gold thin film of 10 nm thickness. A theoretical calculation predicts that the light electric field is enhanced in the SIGN system, even at off-resonance wavelengths. The observed THz field amplitude was quadratic with the illumination light field, suggesting that the THz generation is due to a second-order nonlinear optical process.
基于太赫兹（THz）波长光整流的电磁波发射，是从金表面上方的表面固定金纳米球（SIGNs）观察到的。虽然激发波长与局域表面等离子体失谐，但观察到的 THz 发射场比 10nm 厚的渗透金薄膜的发射场大约大 4.8 倍。理论计算预测，即使在失谐波长下，SIGN 系统中的光电场也会增强。观察到的 THz 场振幅与照明光场呈二次方关系，表明 THz 产生是由于二阶非线性光学过程。
