Study on the characteristic of energy response of large sampling device to ultra-high energy laser diagnosis

In terminal optical system of the ICF (inertial confinement fusion) , the large caliber (310mm*310mm) beam sampling grating (BSG) is used to confirm the energy of the main laser by measuring the -1st transmission diffractive light intensity of the main laser beam.The characteristics of BSG's energy response directly affects the measurement accuracy. The characteristic of BSG's energy response has been studied in this paper based on the actual intensity distribution of the ultra-high energy laser beam and the spatial distribution model of diffractive efficiency of BSG. BSG's energy response affected by its uniformity of the diffractive efficiency has been analysised, too. The results indicate that the spatial distribution of diffractive efficiency of BSG is directly related to the energe response characteristics and the uniformity of BSG's diffractive efficiency has an impact on the accuracy of the sampling of energy.This research provides a theoretical basis for evaluating the high-energy sampling device's energy response characteristic in ultra-high energy diagnosis. The technical indicator with the uniformity of BSG's diffractive efficiency has been attained and these results are use for the fabrication of the beam sampling gratings in practice.