Silver nanoparticles were prepared by pulsed laser ablation technique using a second harmonic wavelength (532 nm) of Q switched Nd:YAG laser of 7 ns pulse width and 10 Hz repetition rates. Formation of Ag NPs was confirmed from characteristic surface Plasmon resonance induced absorption (~418 nm). Spherical shape morphology and crystalline nature of structure were revealed from SEM and TEM analysis. Nonlinear optical studies were conducted by z scan analysis with the same laser system used for ablation. A switching of nonlinear absorption (saturable absorption to reverse saturable absorption) in Ag NPs were observed when on axis input intensity increased from 0.27 GW/cm2 to 0.83 GW/cm2 and it could be attributed to interplay of different nonlinear absorption mechanisms, that is strongly depends on the intensity of the excitation source. Self-defocusing nature of the sample was revealed from the closed aperture z scan analysis.