Fig. 2: Luminescent meta-axicons for collimating ordinarily trapped spontaneous emission.
From: Light-emitting metalenses and meta-axicons for focusing and beaming of spontaneous emission
a SEM image of the meta-axicon. b Back-focal-plane (BFP) image of the meta-axicon illuminated with a normally incident light at a wavelength of 560 nm. The bright spot at the center is the uncoupled incident light. The image is saturated by a factor of 5 to make the ring at \(k=1.06{k}_{0}\), corresponding to the converted light, easily visible. c Theoretically derived, unpolarized emission of the light-emitting meta-axicon. The incident light used for this calculation is the calculated BFP of the InGaN/GaN thin film. d Measured unpolarized emission pattern of the light-emitting meta-axicon. The gray ring corresponds to NA = 1.3.
