What does LASER stand for?

The correct answer is "Light Amplification by Stimulated Emission of Radiation." This phrase accurately describes the fundamental operating principle of a laser.

In this context, "Light Amplification" refers to the process by which light is increased in intensity, a core function of lasers as they generate coherent and focused light beams. "Stimulated Emission" is crucial because it denotes the mechanism by which photons (light particles) are emitted, leading to the amplification of light. When an atom or molecule is excited to a higher energy level and then stimulated by an external photon, it can release additional photons of the same energy, phase, and direction, resulting in a cascade effect that produces a powerful light source. Finally, "Radiation" in this context refers to the emission of light as a form of electromagnetic radiation.

Understanding these components reveals why this specific phrasing is central to the technology and application of lasers across various fields, including medical, industrial, and communication technologies. The other options do not correctly represent the principles of laser operation, thus affirming the correctness of the chosen answer.