The ability to uniquely identify an object or device is important for authentication. Imperfections,locked into structures during fabrication, can be used to provide a fingerprint that is challenging to reproduce. In this talk, I will present a simple optical technique to read unique information from nanometer-scale defects in quantum materials. Imperfections created during crystal growth or fabrication lead to spatial variations in the bandgap of 2D materials that can be characterized through photoluminescence measurements. I will show a simple setup (illustrated in Fig1) involving an angle-adjustable transmission filter, simple optics and a CCD camera can capture spatially-dependent photoluminescence to produce complex maps of unique information from 2D monolayers. Atomic force microscopy is used to verify the origin of the optical signature measured, demonstrating that it results from nanometer-scale imperfections.This solution to optical identification with 2D materials could be employed as a robust security measure to prevent counterfeiting.