GaN Membrane With Nano-Grooves for Single-Band Coupling in the Entire Visible Wavelength Range

Nano-groove arrays incorporated into a freestanding GaN membrane are proposed for coupling with visible light. The coupling of transverse electric mode light over the entire visible wavelength region into and out of the planar membrane is thoroughly investigated herein by performing a finite element method analysis. Coupling can be regulated by device parameters such as groove depth, membrane thickness, grating period, and duty cycle. Single-band coupling featuring tunable coupling bands can be realized, with the peak dual coupling efficiency reaching 0.55. This study paves the way for realizing planar photonics devices at specific single wavelengths. The proposed device is a suitable candidate for use in optical filters, de-multiplexers, planar photonic sensors, and other devices.