LASER stands for which phrase?

LASER stands for which phrase?

• A. Light Amplification by Spontaneous Emission of Radiation
• B. Light Amplification by Stimulated Emission of Radiation
• C. Laser Amplification by Stimulated Emission of Radiation
• D. Light Absorption by Stimulated Emission of Radiation

Answer: (B)

LASER stands for Light Amplification by Stimulated Emission of Radiation. The key idea is that the light beam is produced and amplified through stimulated emission, where an incoming photon causes an excited atom to emit a second photon of the same phase, frequency, and direction. This stimulated process creates coherent, directed light and provides optical gain inside the laser medium. If emission were spontaneous, photons would be emitted in random directions with random phases, giving no consistent amplification or coherence. The other phrasing would either change the word order or replace stimulated emission with absorption or spontaneous emission, which do not describe the mechanism that builds a usable, amplified laser beam.

LASER stands for Light Amplification by Stimulated Emission of Radiation. The key idea is that the light beam is produced and amplified through stimulated emission, where an incoming photon causes an excited atom to emit a second photon of the same phase, frequency, and direction. This stimulated process creates coherent, directed light and provides optical gain inside the laser medium. If emission were spontaneous, photons would be emitted in random directions with random phases, giving no consistent amplification or coherence. The other phrasing would either change the word order or replace stimulated emission with absorption or spontaneous emission, which do not describe the mechanism that builds a usable, amplified laser beam.