Nonlinear optical studies of lead lanthanum borate glass doped with Au nanoparticles

Synthesis, characterization and optical nonlinearity of lead lanthanum borate glass embedded with gold nanoparticles have been investigated. DSC thermogram shows characteristics glass transition temperature at Tg = 775 K. Glasses doped with Au were subjected to heat treatment at 823 K with different annealing time and then, slowly cooled to room temperature show striking ruby color. SAED and TEM analyses have confirmed that f.c.c. Au nanoparticles of ~ 40 nm size are present in these glasses. An absorption peak centered on 563 nm has been observed in heat treated samples, which is attributed to surface plasmon resonance of gold nanoparticles. Nonlinear optical studies with open aperture Z-Scan technique show saturable absorption for heat treated samples at low intensity and reverse saturable absorption in samples without heat treatment at high intensity.