Institute of Physics, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle, Germany.
Opt Lett. 2010 Feb 1;35(3):273-5. doi: 10.1364/OL.35.000273.
Strained silicon is a versatile new type of material, which has found application in microelectronics and integrated optics in the last years. Unlike ordinary silicon, it does not possess a centrosymmetric lattice structure. This allows for stimulation of nonlinear optical processes that involve second-order nonlinear susceptibility. Here, the dependence of the nonlinear susceptibility on the applied strain by means of reflected second-harmonic generation is investigated. This surface-sensitive technique is suitable for the investigation of bulk silicon strained by a layer of thermal oxide. The obtained relation between applied stress and susceptibility enhancement is compared to theoretical prediction based on an analytical model for the deformed silicon orbital. The knowledge of the stress-susceptibility dependence can be used to develop suitable photonic devices that benefit from second-order nonlinear processes in silicon.
应变硅是一种新型的多功能材料，近年来在微电子学和集成光学领域得到了应用。与普通硅不同，它不具有中心对称晶格结构。这使得能够激发涉及二阶非线性极化率的非线性光学过程。在这里，通过反射二次谐波产生研究了非线性极化率对施加应变的依赖性。这种对表面敏感的技术适用于通过热氧化层对体硅进行应变的研究。所获得的外加应力与极化率增强之间的关系与基于变形硅轨道的分析模型的理论预测进行了比较。对外加应力与极化率之间的依赖性的了解可用于开发受益于硅中的二阶非线性过程的合适的光子器件。
