Harmonic Generation up to Fifth Order from Al/Au/CuS Nanoparticle Films

• DOI: 10.1021/acs.nanolett.4c00776
• Publication Date: 2024-04-15T17:14:15Z
• Authors: Yueming Yan; Nathan J. Spear; Qingzhou Meng; Mahi R. Singh; Janet E. Macdonald; Richard F. Haglund
• Keywords: Localized surface plasmon; Harmonic

Dual heterostructures integrating noble-metal and copper chalcogenide nanoparticles have attracted a great deal of attention in nonlinear optics, because coupling their localized surface plasmon resonances (LSPRs) substantially enhances light–matter interactions through local-field effects. Previously, enhanced cascaded third-harmonic generation was demonstrated Au/CuS mediated by harmonically coupled resonances. This suggests promising approach for extending enhancement to higher harmonics adding an additional nanoparticulate material with higher-frequency harmonic the hybrid films. Here we report first observation fourth- fifth-harmonic Al/Au/CuS driven LSPRs at fundamental (1050 nm), second (525 third (350 nm) pump frequency. An analytical model based on incoherent dipole–dipole among plasmonic accounts observed enhancements. The results suggest novel design efficiently generating resonant structures means multiple sum-frequency cascades.