Optimized multi-exposure optical path with a single laser pulse for the measurement of ultra-high speed

High-speed measurements, particularly close to the velocity of light, have always been a great challenge in the field of experimental measurement. Although traditional high-speed measurement methods based on imaging technology can achieve millions of frames per second, they face the problem that the field of view decreases with an increase in the frame rate, which is difficult to overcome in a short period. In this study, a closed multi-exposure optical path is designed first based on a 600 ps pulse laser that realizes the continuous measurement of sub-light velocity and is not subject to the field of view. The path can also be adjusted with respect to time, accurate up to sub-nanoseconds. Second, it is found that the accuracy and resolution of the present method are related to the used pulse laser and camera. Once the performances of the pulse laser and the camera are improved, the corresponding range of measurement of the velocity can be improved further. Compared with traditional pumping technologies, the proposed technology achieves continuous velocity measurement with the utilization rate of laser energy as high as 100%. Finally, we use this novel optical system to determine the flux avalanche velocity of the YBa2Cu3O7-x superconducting thin film, and a highest speed of 323.5 Km/s is obtained.