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A dual sub-pulse train 1064 nm picosecond radially polarized beam pump KGW single-pass Raman generator was designed. The Stokes lines of both the 768 cm−1 and 901 cm−1 vibrational modes of the KGW Raman-active crystal were excited simultaneously. The Raman generator radiated up to seven Stokes lines in the infrared spectrum, which covered multiple optical communication channels. The overall Stokes average power reached 1.01 W, and the maximum Raman overall conversion efficiency was 23.1%. The interaction between the optical field and the Raman crystal was discussed from two perspectives of line width compression and beam quality.

We report high-energy, high-efficiency second harmonic generation in a near-infrared all-solid-state burst-mode picosecond laser at a repetition rate of 1 kHz with four pulses per burst using a type-I noncritical phase-matching lithium triborate crystal. The pulses in each burst have the same time delay ( ${\sim}1~\text{ns}$ ), the same pulse duration ( ${\sim}100~\text{ps}$ ) and different relative amplitudes that can be adjusted separately. A mode-locked beam from a semiconductor saturable absorber mirror is pulse-stretched, split into seed pulses and injected into a Nd:YAG regenerative amplifier. After the beam is reshaped by aspheric lenses, a two-stage master oscillator power amplifier and 4f imaging systems are applied to obtain a high power of ${\sim}100~\text{W}$ . The 532 nm green laser has a maximum conversion efficiency of 68%, an average power of up to 50 W and a beam quality factor $M^{2}$ of 3.5.