Optical spectroscopy is a scientific technique that involves analyzing the interaction between light and matter. This technique is widely used in various fields such as chemistry, physics, biology, and materials science to study the properties of materials based on the light they absorb, emit, or scatter. By measuring the absorption, emission, or scattering of light at different wavelengths, researchers can obtain valuable information about the structure, composition, and dynamics of materials. Optical spectroscopy can be used to characterize molecules, determine concentrations of substances in a sample, and study reaction kinetics, among other applications.