Fig. 3
From: Giant two-photon upconversion from 2D exciton in doubly-resonant plasmonic nanocavity
Physical scenario of enhanced upconversion in plasmonic cavity. a Schematic of the setup for collecting upconverted emissions in our experiments. The inset presents a cross-sectional diagram of the hybrid nanocavity. b, c Far-field angular radiation patterns for monolayer WS2 in the plasmonic cavity (b) and free space (c). d–f Charge and field distribution (|E/E0 | ) around the plasmonic cavity for the mode at the emitted photon energy (2.0 eV). g–i Charge and field distribution (|E/E0 | ) around the plasmonic cavity for the mode at excitation photon energy (1.55 eV)
