Control of spatial coherence of off-the-shelf red LED

Abstract

We investigated our ability to control the spatial coherence of readily available red LED using a revised Young's classical double-slit experiment realized with a digital micromirror device (DMD) and a variable pinhole. Using our method alleviates the difficulties associated with the mechanical arrangements of slits used previously. Measuring the spatial coherence with a dynamic slit afforded by the DMD shows how the coherence of this LED can be tailored for applications beyond lighting decorations. Our experimental results show that even with this type of LEDs, one can make desirable interferograms. This is important because it becomes easier to produce interferograms that are of different wavelengths with cheap LEDs.