Optical characterization is a field of research that involves the measurement and analysis of the optical properties of materials and devices. This can include the study of light absorption, reflection, transmission, scattering, and emission in various types of materials. Optical characterization techniques can provide valuable information about the structural, chemical, and electronic properties of materials, and are used in a wide range of applications, such as in the development of new materials for sensors, photovoltaic devices, displays, and other optoelectronic devices. Some common techniques used in optical characterization include spectrophotometry, ellipsometry, photoluminescence, and reflectance/transmittance measurements.