Fig. 11

Photoluminescence emission in the strong excitation case. a The excitation power dependence of integrated AMPL intensity appears as a typical bi-segmental curve in logarithm coordinate. AMPL threshold locates at around 20.2 kW/cm² and the two slopes are fitted to be b1 = 0.17 ± 0.02 and b2 = 10.87 ± 1.74, respectively. The inset shows a fine structure of the data curve around the threshold. Reprinted with permission from Scientific Reports 2016, 6, 18,857. Copyright 2016 Springer Nature Publishing Group. b Double logarithmic plot of the photoluminescence intensity from a single Au120–Al160 heterodimer as a function of the incident laser intensity. The incident beam is linearly polarized along the long dimer axis. Four regimes with different excitation intensity dependences are divided: ① pre-AMPL step, ② AMPL occurring step, ③ post-AMPL step with continuous increase in the incident intensity and ④ post-AMPL step with decreasing laser intensity. Reprinted with permission from The Journal of Chemical Physics 2021, 154, 074701. Copyright 2021 American Institute of Physics. c Photoluminescence spectra taken below (blue) and above (red) the AMPL threshold, respectively. Open circles with error bars represent the fitted slope values versus photon energy. Reprinted with permission from Scientific Reports 2016, 6, 18,857. Copyright 2016 Springer Nature Publishing Group. d MPL spectra of a single contacted Au120–Al160-g20 nanodimer before (red) and after (blue) the AMPL occurrence. For guiding the eyes, the emission signals of pre-AMPL are multiplied by 25. Reprinted with permission from The Journal of Chemical Physics 2021, 154, 074701. Copyright 2021 American Institute of Physics