4th Physics Institute and Research Center SCoPE, University of Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany.
Nano Lett. 2014 May 14;14(5):2867-72. doi: 10.1021/nl500913t. Epub 2014 Apr 17.
We incorporate dielectric indium tin oxide nanocrystals into the hot-spot of gold nanogap-antennas and perform third harmonic spectroscopy on these hybrid nanostructure arrays. The combined system shows a 2-fold increase of the radiated third harmonic intensity when compared to bare gold antennas. In order to identify the origin of the enhanced nonlinear response we perform finite element simulations of the nanostructures, which are in excellent agreement with our measurements. We find that the third harmonic signal enhancement is mainly related to changes in the linear optical properties of the plasmonic antenna resonances when the ITO nanocrystals are incorporated. Furthermore, the dominant source of the third harmonic is found to be located in the gold volume of the plasmonic antennas.
我们将介电铟锡氧化物纳米晶纳入金纳米间隙天线的热点区域，并对这些混合纳米结构阵列进行了三次谐波光谱分析。与裸金天线相比，组合系统显示出辐射三次谐波强度增加了两倍。为了确定增强的非线性响应的起源，我们对纳米结构进行了有限元模拟，该模拟与我们的测量结果非常吻合。我们发现，当掺入 ITO 纳米晶时，三次谐波信号增强主要与等离子体天线共振的线性光学性质的变化有关。此外，还发现三次谐波的主要来源位于等离子体天线的金体中。
