Hybrid plasmonic–dielectric metal-nanowire coupler for high-efficiency broadband nonlinear frequency conversion

Abstract

Pursuing nanometer-scale nonlinear converters based on second harmonic generation (SHG) is a stimulating strategy for bio-sensing, on-chip optical circuits, and quantum information processing, but the light-conversion efficiency is still poor in such ultra-small dimensional nanostructures. Herein, we demonstrate a highly enhanced broadband frequency converter through a hybrid plasmonic–dielectric coupler, a ZnTe/ZnO single core–shell nanowire (NW) integrated with silver (Ag) nanoparticles (NPs). The NW dimension has been optimized to allow the engineering of dielectric resonances at both fundamental wave and second harmonic frequencies. Meanwhile, the localized surface plasmon resonances are excited in the regime between the Ag NPs and ZnTe/ZnO dielectric NW, as evidenced by plasmon-enhanced Raman scattering and resonant absorption. These two contributors remarkably enhance local fields and consequently support the strong broadband SHG outputs in this hybrid nanostructure by releasing stringent phase-matching conditions. The proposed nanoscale nonlinear optical converter enables the manipulation of nonlinear light–matter interactions toward the development of on-chip nanophotonic systems.

Control of laser-plasma instabilities by non-collinear polychromatic light

“…A 20 mm long KD 2 PO 4 (DKDP) crystal is used for SHG (cutting angles of Θ = 36.6 • and Φ = 45 • , type-I phase matching). The corresponding energy evolutions of the fundamental wave and second harmonic in the DKDP crystal are displayed in figure 5(a) [66][67][68][69]. The second harmonic is separated from the residual fundamental wave via dichroic mirror 1 (DM1; 1053 nm and 1072 nm transmission, 526.5 nm reflection) with an output energy of 4.25 kJ, which corresponds to a conversion efficiency of approximately 85%.…”