Fig. 1. Schematic diagram of a QED cascade in a super-strong laser field, double solid lines directed rightwards/leftwards represent electrons/positrons, and wavy lines represent high-energy photons

Fig. 2. Maximum value of parameter as a function of laser intensity ( ) in the case of counter-propagating linearly polarized lasers 在两束线偏振激光对向碰撞情况下，参数 的最大值与激光强度（ ）的变化关系

Fig. 3. Photon emission probability and positron-electron pair creation probability as a function of laser intensity ( ) in the case of counter-propagating linearly polarized lasers 在两束线偏振激光对向碰撞情况下，伽马光子发射和正负电子对产生的概率与激光强度的变化关系

Fig. 4. Spatiotemporal evolutions of the positron (a) and (c) and high-energy photon (b) and (d) densities at y = 0 in the case of counter-propagating linearly polarized lasers interaction with solid targets, where sub figures (a) and (b) and (c) and (d) are shown for the cases with the laser intensities of 4×10²³ and 1.2×10²⁴ W/cm², respectively ^[36]