Flash photolysis is an experimental technique in chemistry and physics used to study short-lived chemical species and transient reactions by employing short and intense flashes of light to initiate photochemical reactions. In this method, a brief and intense light pulse, often from a flash lamp or laser, is directed at a sample, causing photochemical reactions to occur. The short duration of the light pulse allows researchers to capture and study the rapid intermediate steps of chemical reactions that take place on timescales ranging from microseconds to milliseconds. Flash photolysis has been instrumental in elucidating reaction mechanisms, studying excited states of molecules, and exploring the dynamics of various chemical and biological processes.