Planar layers of Au clusters with diameters between 5 and 30 nm were synthesized by implanting 2.75-MeV Au+ ions in fused silica. The metal-glass composite layer was 0.85 μm below the surface and had a width of 0.5 μm. Thermal annealing enhanced the optical absorption of the annealed samples near 2.4 eV. The third-order nonlinear optical response time is ≤35 ps; the magnitude of the effective nonlinear susceptibility is 200 times that of similar clusters embedded in ruby-gold melt glass.

Synthetic two-dimensional transition metal dichalcogenides such as, tungsten disulphide (WS₂), tungsten diselenide (WSe₂), molybdenum disulphide (MoS₂) as well as mixed molybdenum tungsten disulphide (Mo_0.5W_0.5S₂) single crystals were grown by the chemical vapor transport method using halogens (bromine or chlorine) as transport agents. Multi- layer samples were cleaved from the single crystals, and their nonlinear optical (NLO) properties were obtained from both open aperture and closed aperture Z-scan measurements using a picosecond mode-locked Nd: YAG laser operating at a wavelength of 1064 nm, with pulse duration of 25 ps, and 20 Hz repetition rate. Both WS₂ and MoS₂ exhibited nonlinear saturable absorption (SA), whereas WSe₂ and Mo_0.5W_0.5S₂ showed nonlinear two-photon absorption (2PA). A large 2PA coefficient β as high as + 1.91x10^-8 cm/W was obtained for the Mo_0.5W_0.5S₂, and an index of refraction coefficient γ = -2.47x10^-9 cm²/W was obtained for the WSe₂ sample.