Stimulated emission is a process in which an incoming photon causes an excited atom or molecule to release its energy in the form of another photon. This newly emitted photon has the same energy, phase, and direction as the incoming one. This phenomenon is fundamental to the operation of lasers, where a chain reaction of stimulated emissions produces a coherent beam of light. In a laser, a medium, such as a gas or crystal, is energized to create a population of excited atoms. When these atoms encounter a photon, they can be stimulated to emit additional photons, amplifying the light. This process is essential for technologies like lasers, which are used in various applications, including medical procedures, communication, and manufacturing.