281 / 2023-04-25 09:31:50

Ultrafast optical imaging for the observation of highly dynamic phenomena

ultrafast imaging,optical imaging,femtosecond laser,optical time stretch

极端光下的基础物理学 > 基础物理-I

Observing ultrafast physical phenomena arising from the interaction between high-power laser and matter has long been a hot topic in the fields of high-energy-density physics, ultrafast optics, and laser material processing. Time-resolved ultrafast optical imaging technologies are important tools to understand many fundamental issues in the interaction of light and matter, such as photoexcited electron thermalization, phonon relaxation, plasma formation, thermal diffusion and shock wave generation, and molten pool dynamics. Here, by utilizing the principle of optical time-stretch, we demonstrate ultrafast optical imaging with a temporal resolution ranging from the nanosecond to the femtosecond level. Specifically, we measured the evolution of the material surface under laser processing using optical time-stretch (OTS) imaging with a continuous temporal resolution of the nanosecond level. Meanwhile, we achieved hybrid-mapping sequentially timed all-optical mapping photography (STAMP) with a frame rate over THz and a frame number of 25 during a single shot, with which we recorded the process of the generation and evolution of plasma induced by the interaction of high-power laser and glass/air. Furthermore, our ultrafast imaging system can capture both the intensity and phase of the probe pulse and switch between the continuous-imaging mode and single-shot mode with diffraction-limit spatial resolution. We believe our method can play an important role in the observation of various ultrafast phenomena, including inertial confinement fusion (ICF), laser-driven particle accelerators, strong-field quantum electrodynamics, and laser material processing.