Fig. 1. Experimental device diagram and cascaded nonlinear frequency conversion schematic

Fig. 2. Output spectra of LD pump power variation.(a) Spectrum of 0.6 W output power; (b) spectrum of 0.9 W output power; (c) spectrum of 1.7 W output power

Fig. 3. Average output power and pulse width as a functions of LD pump power

Fig. 4. Pulse energy and peak power as a function of LD pump power

Fig. 5. Spontaneous Raman scattering spectrum of KTP crystal with X(ZZ)X structure

Fig. 6. Transverse mode distribution of red laser

Fig. 7. Waveforms of single pulses and pluse train with different output wavelengths. (a) Red laser waveforms; (b) pulse waveforms of OPO signal at 1572 nm; (c) pulse waveforms of fundamental wave at 1064 nm