What does 'laser' stand for?

'Laser' stands for "Light Amplification by Stimulated Emission of Radiation." This term describes the fundamental principles behind how lasers function. In a laser, light is produced through the process of stimulated emission, where an incoming photon prompts an excited electron in an atom to release a photon of its own, creating a chain reaction that results in light amplification. The characteristics of laser light, such as coherence, monochromaticity, and directionality, are a direct result of this process.

The other options reflect some components related to light and energy but do not accurately represent the fundamental science of lasers. For example, the terms in other choices mix concepts or misinterpret the processes involved in laser operation. Understanding the correct definition is crucial, as it encapsulates both the technology and the scientific principles that enable lasers to be widely used in various applications, from medical instruments to communication technologies.