We developed a compact Yb:YAG ceramic regenerative amplification system. A rectangular glass block is used to
elongate the cavity. A pulse to be amplified is propagated in a long distance in the glass block by being reflected
repetitively at the end faces of the glass under a condition of total internal reflection. Furthermore, we produced
transmission gratings with a diffraction efficiency of more than 95%. The floor area of the entire amplification system is
reduced to less than 2,000 cm<sup>2</sup>. In 20-kHz operation, the system generates 1.0-ps compressed pulses of 4.5-W average
power, i.e., 0.225-mJ energy.