Fig. 6: Controlling emission polarization of electroluminescent metasurfaces made by 1D arrays of nanorod OLED pixels.
From: Scalable nanopatterning of organic light-emitting diodes beyond the diffraction limit
a,d, SEM images for 1D arrays of EML nanorods deposited on glass with p values of 350 nm (a) and 450 nm (d). b,e, Experimental (Exp.) and simulated (Sim.) radiation patterns of the structures in a (b) and d (e) that display emission directionality along the \({k}_{y}=0\) axis. c,f, Experimental maps of the \({{\rm{S}}}_{1}/{{\rm{S}}}_{0}\) Stokes parameter characterizing the degree of linear polarization as a function of in-plane momentum of the patterns in a (c) and d (f). The left maps exhibit linearly polarized PL along the nanorod long axis at all momenta for EML nanostructures on glass. On the contrary, the EL maps for the nano-OLED devices (right) reveal that the EL polarization is strongly influenced by leaky waveguide and plasmonic modes, such that the \(p=350\) nm nanorod arrays yield p-polarized light (\({{\rm{S}}}_{1}/{{\rm{S}}}_{0} < 0\)) at low \({k}_{y}\), whereas the \(p=450\) nm nanorod arrays remain to yield s-polarized light (\({{\rm{S}}}_{1}/{{\rm{S}}}_{0} > 0\)) at all angles. A change in the nanorod periodicity reverses the electroluminescent polarization at the perpendicular angle, \(k=0\).
