Fig. 1. Basic schematic diagram of regenerative amplifier

Fig. 2. Diagram of regenerative cavity（QS and CD are Pockels cells for Q switch and cavity dump；A is aperture）

Fig. 3. Schematic of diode-pumped regenerative amplifier （DL，diode-laser array；L1，microlens array；L2，cylindrical lens； L3，spherical lens；WG，wedged glass plate）

Fig. 4. Schematic diagram of Nd:YLF ring amplifier（SLM-FL， single longitudinal mode fiber laser；EP，beam expander； SA，serrated aperture；PBS，polarization beam splitter； VSF，vacuum spatial filter；PCP，phase conjugate plate）

Fig. 5. Diagram of experimental setup（HR，high reflectivity mirror）

Fig. 6. Diagram of laser system（CM，chirped mirror；PP-MgO:LN，MgO-doped periodically poled LiNbO₃ crystal；RTP，rubidium titanyl phosphate）

Fig. 7. Diagram of ring cavity（L1 and L2，adjustable lenses； W1 and W2，windows of vacuum spatial filter）

Fig. 8. Optical setup of regenerative amplifier （vex，convex mirror；cav，concave mirror）

Fig. 9. Diagram of detailed setup of the regenerative amplifier