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脉宽测量系统。采用分子束外延技术生长了光折变量子阱结构。经过机械加工和化学加工，自行制作了光学器件。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。光栅写入激光被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干涉而不聚焦。利用光谱仪检测量子阱中光栅结构的衍射光束，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所需的性质。未来，将使用我们的光学设备进行脉冲宽度测量。此外，利用非线性BaB 2 O 4晶体，通过共线二次谐波产生几何结构测量了超短激光脉冲的持续时间。取得了良好的效果。用氧化物光学晶体制作非线性工艺简单易行。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.