The synthesis of bimetallic gold plus nickel nanoparticles dispersed in a glass host and behavior-enhanced optical nonlinearities

A sol-gel synthetic route toward the fabrication of bimetallic gold plus nickel nanoparticles (NPs) in sodium borosilicate glasses is presented, with controlled atmosphere heat treatments. Characterizations of the as-obtained glasses indicate that when exposed to variable atmospheres of oxygen (O2) and oxygen (O2)-hydrogen (H2), randomly distributed Au/NiO NPs and Au/Ni NPs are produced in the glass host, respectively. Subsequently, the Z-Scan technique is conducted to examine their nonlinear optical response with femtosecond pulses. The two glasses show superior optical nonlinearities comparable to that of the glasses incorporated with Au NPs. For the glass dispersed with Au/NiO NPs, the enhancement of the third-order nonlinear response mainly depends on a contribution of a stronger nonlinear refraction response. However, the dominant contribution to improve optical nonlinearities of the glass doped with Au/Ni NPs is the more intense nonlinear absorption effect.