Stimulated emission

Definition

Stimulated emission is the process by which an incoming photon causes an excited electron to drop to a lower energy level, releasing a second photon. This emitted photon has the same phase, frequency, polarization, and direction as the incoming photon.

5 Must Know Facts For Your Next Test

1. Stimulated emission was first proposed by Albert Einstein in 1917.
2. It is a fundamental principle behind the operation of lasers.
3. The process requires an external photon that matches the energy difference between two electron states.
4. Stimulated emission results in coherent light, where all photons have identical properties.
5. The rate of stimulated emission increases with the intensity of the incoming light.

Review Questions

Related terms

Spontaneous Emission:

The process by which an excited electron independently falls to a lower energy state and emits a photon without external influence.

Population Inversion:

A condition where more electrons are in an excited state than in lower energy states, crucial for laser operation.

Coherent Light:

Light waves that are phase-locked with each other. In lasers, this results from photons being emitted through stimulated emission.