700 W, <10 ps, two-stage in-band pumped Nd:YVO4 Innoslab amplifier with high efficiency.

In this paper, a high efficiency in-band pumped two-stage Nd:YVO₄ partially pumped slab (Innoslab) picosecond amplifier with a pulse duration <10 ps is demonstrated. The output characteristics of the second stage amplifier under different saturated injection laser power are studied through simulation and experiments. And being benefit from the in-band pumping technique, the excellent thermal management and the good mode matching of the Innoslab amplifier design, an average output power of 700 W with a pulse duration of 9.8 ps at 2 MHz is obtained finally, and total pump power is 1449 W, corresponding to the overall optical-to-optical conversion efficiency of 47.7%. The maximum extraction efficiency of the second amplifier reaches 54.8%. The beam quality factors M² at the maximum output power in the horizontal and vertical directions are measured to be 1.36 and 1.06, respectively.