What does 'laser' stand for?

The term 'laser' stands for "Light Amplification by Stimulated Emission of Radiation." This definition captures the fundamental principle behind how lasers operate. The process begins with light amplification, where photons are produced and increased in intensity through stimulated emission. This occurs when an electron in an excited state drops to a lower energy level, releasing energy in the form of light. This emitted light is then further amplified as it bounces back and forth between mirrors in the laser cavity, resulting in a coherent beam of light that is highly focused and monochromatic.

Understanding this definition is crucial for grasping the basic science behind laser technology, as it highlights the importance of stimulated emission and how it differentiates lasers from other forms of light generation. The other choices, while they contain terms related to light and energy, misrepresent the core concept and function of lasers, making them inaccurate.