Second-harmonic generation of embedded plasmonic nanoparticle arrays via interparticle coupling

Efficient nonlinear frequency conversion, such as second-harmonic generation in ultracompact structures, is essential for the development of modern nanophotonic devices. Here, we demonstrate intense emission scalable embedded Ag nanoparticle arrays fabricated by ion implantation into BK7 glass. The interparticle coupling effect significantly enhances local field at nanogap (gap size ? 1 nm) two neighboring nanoparticles and finally amplifies generated surface plasmonic nanoparticles. Notably, intensity comparable to that two-dimensional transition metal dichalcogenides under excitation a fundamental wave 1064 nm independent incident polarization angles. Our work offers promising strategy on rapid fabrication low-cost optical nanostructures with great environmental stability.