Chen Kai, Durak Cemil, Heflin J R, Robinson Hans D
Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA.
Nano Lett. 2007 Feb;7(2):254-8. doi: 10.1021/nl062090x.
We have demonstrated large enhancements of the effective second-order nonlinear susceptibility (chi(2)) of ionic self-assembled multilayer (ISAM) films, causing a film with just 3 bilayers to be optically equivalent to a 700-1000 bilayer film. This was accomplished by using nanosphere lithography to deposit silver nanoparticles on the ISAM film, tuning the geometry of the particles to make their plasmonic resonances overlap the frequency of optical excitation. An enhancement in the efficiency of second harmonic generation (SHG) by as much as 1600 times was observed. Even though this is already a large value, we suggest that further refinements of the techniques are expected to lead to additional enhancements of similar or larger magnitude.
我们已经证明了离子自组装多层（ISAM）薄膜的有效二阶非线性极化率（χ(2)）有大幅增强，使得仅3个双层的薄膜在光学上等同于700 - 1000个双层的薄膜。这是通过使用纳米球光刻技术在ISAM薄膜上沉积银纳米颗粒来实现的，调整颗粒的几何形状以使它们的等离子体共振与光激发频率重叠。观察到二次谐波产生（SHG）效率提高了多达1600倍。尽管这已经是一个很大的值，但我们认为该技术的进一步改进有望带来类似或更大幅度的额外增强。
