Abstract Draft

       

Abstract Draft

      Femtosecond laser has been widely used for optical and photonics fabrication due to its extremely short pulse duration and high intensity. Ultrafast pump-probe imaging is used to visualize the dynamic phase changes of optical substrates (silicon, silicon carbide, glass, etc.) by splitting the femtosecond laser beams into pump beams and probe beams. Pump beam (high energy) ablates the sample to remove the materials by direct vaporization. Probe beam (low energy) reflects from the sample surface to a CCD camera to give an image of the surface structure after a delay time. After calibrating the zero time delay point, different surface structures will be observed and gathered by changing the time delay line. Laser-induced structural changes in optical substrates will then be dynamically imaged and characterized by analyzing the surface structure.