Measuring lifetime and magnitude of the optical Kerr-effect in tailored bandgap materials

在该项目的第一阶段，我们首次获得了介质中三阶极化的非瞬时响应的实验证据。我们研究了利用红外振荡器产生的6-fs脉冲产生的三次谐波。为了系统地评估响应时间，我们使用三元混合氧化物作为带隙可调的非线性介质，在后续的实验中，提出了一种新的实验类型，其中通过光谱干涉测量揭示了光学克尔效应的非瞬时寿命。为此，在材料禁带附近用一种新的几个周期的紫外光光源在激光波长附近的三元氧化物厚层中诱导克尔效应。延迟的非线性传播方程的解支持了测量结果。

During the first period of the project we had been able to get the first experimental evidence for a non-instantaneous response of the third-order polarization in dielectrics. We investigated the third harmonic generation using 6-fs pulses from an infrared oscillator. For systematic evaluation of the response time, we used ternary mixture oxides as nonlinear media with tunable bandgaps.For the follow-up period a new type of experiment is proposed, where the non-instantaneous lifetime of the optical Kerr effect is revealed via spectral interferometry. For that purpose, a new few-cycle source in the UV is used to induce the Kerr effect in thick ternary oxide layers with laser wavelengths in the vicinity of the materials bandgap. The measurements are backed up with solutions of the delayed nonlinear propagation equation.