This work experimentally introduces a new single-crystal Nd:YAG end-pumped zigzag slab (EPZS) gain module based on a thin polytetrafluoroethylene (PTFE) sheet as a total internal reflection (TIR) protection layer. In this gain module, a specific optical pump-beam delivery (OPBD) system is used to improve the output beam quality (BQ) of the slab amplifier from 9.4 in a typical OPBD system to 4.7 with the total pump power of 2400 W. The average logarithmic small-signal gain (g0l) in the 0.06% Nd:YAG EPZS gain module at the laser beam incident angle of 7.1° was obtained around 0.64 for the two OPBD systems mentioned above.