Fig. 5: Unidirectional emission and radiation control.
From: Switchable unidirectional emissions from hydrogel gratings with integrated carbon quantum dots
a Schematic of the unidirectional PL from Q-HIG. The hydrogel grating steers the PL toward the diffraction order with the far-field emission momentum |k//| + |kG | (m = −2) under the left excitation. b, c Measured angle-resolved PL intensity under the middle and high RH conditions. The intensities of PL measurements are normalized to the same scale. d Line plots for corresponding measured PL intensities in (b, c) at 632-nm wavelength (dashed lines). e Schematic of the PL emission with the emission momentum -|k//| + |kG | (m = 2) under the right excitation. f, g Measured angle-resolved PL intensity (f) enhancement and (g) disappearance at different RH conditions. h Line plots for corresponding PL intensities alteration in (f, g) with a narrow divergence angle of 1.14°, as marked by dashed lines.
