Fig. 1. Schematic diagram of experimental system of 257 nm deep ultraviolet picosecond laser

Fig. 2. Spot energy distribution of 1030 nm fundamental frequency laser

Fig. 3. Measurement spectrum of 257 nm ultraviolet laser

Fig. 4. Laser output powers of 1030 nm fundamental frequency light and 257 nm ultraviolet light as a function of total pump power

Fig. 5. Output spot energy distribution of the fourth harmonic at 257 nm

Fig. 6. Measurement chart of quality factor M² for 257 nm UV laser beam

Fig. 7. Measurement of pulse width by autocorrelator

Fig. 8. 257 nm UV laser frequency measurement chart