Comparison of passively Q-switched laser performance of two composite Nd:YVO $$_{4}$$ 4 /Nd:YVO $$_{4}$$ 4 /Nd:YVO $$_{4}$$ 4 crystals with Cr $$^{4+}$$ 4 + :YAG saturable absorber

Abstract

The passively Q-switched Nd:YVO $$_{4}$$ /Nd:YVO $$_{4}$$ /Nd:YVO $$_{4 }$$ 1.06- $$\upmu $$ m laser has been demonstrated by using Cr $$^{4+}$$ :YAG as saturable absorber. The characteristics are compared under different Nd-doped concentrations of laser crystals and different initial transmissions (T $$_0 )$$ of saturable absorbers. With an incident pump power of 6.52 W, the composite Nd(0.1 at.%):YVO $$_{4}$$ /Nd(0.5 at.%):YVO $$_{4}$$ /Nd(1.0 at.%):YVO $$_{4}$$ laser obtained the maximum average output power of 932 mW and the largest single pulse energy of 5.1 $$\upmu $$ J when T $$_0 =88$$ %. The shortest pulse width of 25 ns and the highest peak power of 177.4 W were achieved with T $$_0 =79$$ % for the composite Nd(0.1 at.%):YVO $$_{4}$$ / Nd(0.3 at.%):YVO $$_{4}$$ /Nd(0.8 at.%):YVO $$_{4}$$ crystal.