Methods and apparatus for screening diverse arrays of materials are provided. In particular, techniques for rapidly characterizing compounds in arrays of materials in order to discover and/or optimize new materials with specific desired properties are provided. The substrate can be screened for materials having useful properties, and/or the resulting materials can be ranked, or otherwise compared, for relative performance with respect to useful properties or other characterizations. In particular, systems and methods are provided for screening a library of magnetic materials for their bulk magnetization, saturation magnetization, and coercivity by imaging their individual optical Kerr rotation, screening a library of dielectric materials for their dielectric coefficients by imaging their individual electro-optical rotation and screening a library of luminescent materials by imaging their individual luminescent properties under a variety of excitation conditions. Optical or visible luminescence systems are also provided as well as their application to screening libraries of different materials.