Highly Collimated Light Emission of Deep‐Ultraviolet Light‐Emitting Diodes Using Fresnel Zone Plate Nanodiffraction Patterns

Fresnel zone plates (FZPs) are diffractive optical structures composed of many symmetrical concentric rings and are widely used in nanofocusing and beam collimation. In this article, the effect of substrate thickness on the beam collimation and light‐extraction efficiency (LEE) enhancement of deep‐ultraviolet (DUV) micro‐light‐emitting diodes (micro‐LEDs) with FZPs are experimentally analyzed. The far‐field patterns and LEE enhancements of the DUV micro‐LEDs are effectively controlled by the FZPs. Optimization of the substrate thickness provides FZP‐containing DUV micro‐LEDs that display highly collimated, optics‐free emission with an emission‐angle full width at half maximum of 9° and high LEE enhancement of 1.4 times.