Mirror testing is a research area that focuses on the development and evaluation of various methods for testing mirrors used in optical systems. This includes testing the surface quality, reflectivity, and overall performance of mirrors to ensure their accuracy and reliability in applications such as telescopes, microscopes, and lasers. Mirror testing involves a range of techniques including interferometry, scatterometry, and profilometry to measure and analyze the properties of mirrors. The goal of mirror testing is to ensure that mirrors meet the required specifications and standards for optimal performance in optical systems.