Measurement Systems for duration of ultra-short pulse laser with degenerate four waves mixing

研究了简并四波混频超短脉冲激光持续时间的测量系统。采用分子束外延法生长光折变量子阱结构。经过一定的机械和化学加工，我们自制了光学器件。为了表征这些量子阱结构光学器件的衍射特性，我们进行了简并四波混频实验。光栅写入激光器通过一个立方体分束器分成两束。这两束光在量子阱光学器件中相互干扰而不聚焦。利用光谱仪对量子阱中光栅结构的衍射光束进行检测，以表征光学器件的衍射能力。从我们的光学器件中可以观察到理想的性能。在未来，脉冲持续时间的测量将使用我们的光学设备进行。此外，利用非线性BaB2O4晶体，利用共线二次谐波产生几何测量了超短激光脉冲的持续时间。取得了良好的效果。氧化光学晶体的非线性过程易于使用。然而，它需要使用高功率激光束。

Measurement system for duration of ultra-short pulse laser with degenerate four-wave mixing process has been investigated. Photorefractive quantum well structure was grown by molecular beam epitaxy. After some mechanical and chemical processing, optical devices were fabricated by ourselves. In order to characterize the diffraction properties of these optical devices of quantum well structure, we perform degenerate four-wave mixing experiment. The grating writing laser is split into two beams by a cube beam splitter. These two beams interfere in the quantum well optical device without foucusing. The diffracted beam from the grating structure in quantum well is detected using a spectrometer to characterize the diffraction ability of the optical device. The desirable property can be observed from our optical devices. In the future, pulse duration measurement will be carried out by using our optical devices. In addition, the duration of ultra-short laser pulse was measured by collinear second harmonic generation geometry by using nonlinear BaB2O4 crystal. Good results were obtained. Nonlinear process with oxide optical crystal is easy to use. However, it needs to use high power laser beams.