Fig. 3: Directional PL emission from Q-HIG.
From: Switchable unidirectional emissions from hydrogel gratings with integrated carbon quantum dots
a Top-view of the fabricated hydrogel grating under the illumination of the halogen lamp and 532-nm pump. Scale bar, 10 μm. b, c Measured angle-resolved dispersion diagrams of PL emission from PVA-CQDs (b) thin film and (c) grating, respectively. d Corresponding far-field radiation polar plots of PL for films (orange) and gratings (purple) at a wavelength of 575 nm. e Measured the polarization component of PL for s-polarization (S-pol.) and p-polarization (P-pol.) using an analyzer. f Calculated enhancement and divergence angle Δθ of the directional PL emission. The value of enhancement is calculated by Igrating/Ifilm, where Igrating is the PL intensity of the grating at the diffractive order, and Ifilm is the PL intensity of the film at the same angle. The divergence angle Δθ is defined by the full width at the half-maximum of the emission angle.
