Hsieh Chia-Lung, Pu Ye, Grange Rachel, Psaltis Demetri
School of Engineering, EPFL, Station 17, 1015 Lausanne, Switzerland.
Opt Express. 2010 May 24;18(11):11917-32. doi: 10.1364/OE.18.011917.
We study second harmonic generation (SHG) from non-centrosymmetric nanocrystals under linearly polarized (LP) and circularly polarized (CP) excitations. Theoretical models are developed for SHG from nanocrystals under both plane-wave and focused excitations. We find that the focused excitation reduces the polarization dependency of the SHG signal. We show that the SHG response under CP excitation is generally inferior to the average of LP excitations over all orientations. We verify the theory by measuring the SHG polar responses from BaTiO3 nanocrystals with a scanning confocal microscope. The experimental data agrees well with the theory.
我们研究了非中心对称纳米晶体在线偏振（LP）和圆偏振（CP）激发下的二次谐波产生（SHG）。针对平面波和聚焦激发下纳米晶体的SHG建立了理论模型。我们发现聚焦激发降低了SHG信号的偏振依赖性。我们表明，CP激发下的SHG响应通常低于所有取向上线偏振激发的平均值。我们用扫描共聚焦显微镜测量BaTiO3纳米晶体的SHG偏振响应来验证该理论。实验数据与理论吻合良好。
