Fig. 4
From: Giant two-photon upconversion from 2D exciton in doubly-resonant plasmonic nanocavity
Thermal tuning upconversion for plasmon−exciton coupling system. a Temperature-dependent PL peak position for WS2 on Au/SiO2/Si. Yellow lines: fitted results by Varshni equation. b Scattering spectrum (yellow dots) of the hybrid system and PL spectrum of the pristine monolayer WS2 at 350 K (red curve) and 300 K (blue curve) on the Au/SiO2/Si substrate. The measured scattering spectrum is fitted with Gaussian functions (yellow curve). c Excitation power-dependent integrated upconverted emission intensity (down) and enhancement (top) for monolayer WS2 in the designed plasmonic cavity. The experimental results (scattering points) can be fitted well by the green and yellow dotted lines based on the power law formula I = bPα. In the illustration above, red (blue) dots represent the enhancement factor at 350 K (300 K). The inset is a schematic diagram of the plasmonic cavity structure
