Photodynamics is the study of the physical properties and behavior of light in biological systems. It is a field encompassing a wide range of applications, including photobiology, photochemistry, and photophysics. There are several synonyms for photodynamics, such as photobiophysics, photobiology, photochemistry, photophysics, and optogenetics. Photobiophysics involves the use of light to understand the biological processes, while photobiology is the study of life and its processes using light. Photochemistry, on the other hand, focuses on the chemical reactions caused by light, while photophysics examines the interactions between light and matter. The emerging field of optogenetics uses light to control and manipulate biological processes at the cellular level.