The optical non linearity of metal nano particles in dielectrics is of special interest because of their high polarizability and ultra fast response that can be utilized in potential device applications. In this study nano composite thin films containing in situ generated Ag nano particles dispersed in an aliphaticur ethane acrylate (AUA) matrix were synthesized using electron beam cu ring technique, in presence of an optimized  concentration of diluents Trimethylolpropanetriacrylate (TMPTA). The metal nano composite films were characterized using UV–visible spectrophotometry, transmission electron microscope (TEM) and field emission scanning electron microscope (FE-SEM) techniques. Ag nano particle impregnated films demonstrated an absorption peak at ∼420 nm whose intensity increased with increase in the Ag concentration. The optical limiting property of the coatings was tested using an anosecond Nd-YAG laser operated at third harmonic wave length of 355nm. For a 25ns pulse and 10Hz cycle, Ag-polymer coatings showed good optical limiting property and the threshold fluence for optical limiting was found to be ∼3.8x10^–2J/cm² while the transmission decreased to 82%. The non linear optical coefficients were also determined using the standard Z-scan technique with picoseconds (∼2 ps,1kHz) and fem to second (∼150fs,100MHz) pulses. Open aperture Z-scan data clearly suggested two-photon absorption as the dominant non linear absorption mechanism. Our detailed studies suggest these composites are potential candidates for optical limiting applications.