Figure 4. HHG from triangular nanographenes.

We show the emission intensity from doped graphene nanotriangles (armchair edges, equilateral 15 nm side length) as a function of incident and emitted photon energies, calculated within the TB-RPA approach upon pulse irradiation (100 fs FWHM duration, 10¹² W m⁻² peak intensity). We consider (a) undoped and (b) doped (E_F=0.4 eV) triangles. The emission intensity in both contour plots is normalized to the overall maximum value of Fig. 4b (Supplementary Fig. 2 shows data normalized to the maximum for each incident photon energy). The upper plots show the linear absorption spectrum and the orientation of the normally incident light polarization (insets).