High-resolution and High-Contrast Imaging of Defects in a Crystal

Abstract

Optically active color centers in crystals provide important building blocks for quantum applications. However, conventional confocal fluorescence microscopy of high-refractive-index crystals suffers from limited photon collection efficiency and spatial resolution. Here, we demonstrate high-resolution, high-contrast imaging of defects in diamonds using microsphere-assisted confocal microscopy. A microsphere provides an excellent optical interface for point defects with a magnified virtual image that increases the spatial resolution up to λ/5, as well as the optical signal-to-noise ratio by four times.