Ultraviolet third-order nonlinear optical response from light-emitting copper nanoclusters embedded in silica

Abstract Third-order nonlinear optical response and photoluminescence emission from Cu nanoclusters synthesized by ion implantation in fused silica are reported. The mean size of the Cu nanoclusters is about 2–3 nm as determined by transmission electron microscopy and they do not exhibit plasmon resonances. The Cu nanoclusters show intense orange photoluminescence emission whose intensity is controlled by the thermal annealing used to nucleate the metallic clusters, and it is quenched for larger clusters of about 9 nm, nucleated at higher annealing temperatures, which exhibit a typical localized Mie resonance at 540 nm. The estimated third-order effective susceptibility, χ ( 3 ) , is about 1.6 × 10 − 9 and 0.9 × 10 − 9 esu for Cu nanoclusters and nanoparticles, respectively. The enhanced Kerr nonlinearities and photoluminescence emissions can be attributed to the molecular-like behavior of the ultrasmall size of the Cu nanoclusters. These findings have potential applications in ultraminiaturized solid-state optoelectronic devices operating at ultraviolet wavelengths such as all-optical switches, optical logical gates, and nano-emitters, among others.