Remote GaN metalens applied to white light-emitting diodes.

In this work, a gallium nitride (GaN) metalens as a remote device has been applied to a commercially available white light-emitting diode (LED). We show the successful demonstration in fabricating the high-aspect-ratio GaN metalens capable of diffraction-limited focusing with an experimentally focusing efficiency up to 89% at the wavelength of 450 nm. The metalens can also resolve the subwavelength features as imaging. For the proof of concept, the rainbow-like phenomenon can be observed by using the remote GaN metalens to disperse the white light radiated by the white LED. The diode lasers working at various wavelengths have been employed to carefully verify the positions of colors in the rainbow-like profile. The results in this study can inspire the semiconductor manufacturing industry at integrating metalenses of various kinds and functionalities into the package of LED modules in the near future and prospect widespread applications in advanced solid-state lighting.