Differennce between spontaneous and stimulated emission
Answers
Explanation:
The terms spontaneous emission and stimulated emission sometimes get confused. The term thermal emission sometimes gets thrown into the mix as well. Here are the basic definitions to help sort things out and the procedures for measuring these parameters.
When we speak of spontaneous or stimulated emissions we are referring to atoms whose electrons are dropping from an excited state to a lower state, emitting a photon. Specifically, the electron emits a photon, then drops from an outer orbit to an inner orbit around the atomic nucleus. The mechanisms for how this happens are different in spontaneous and simulated cases.
Spontaneous emission is the mechanism responsible for most ordinary light. There are different names assigned to the phenomenon depending on how the atoms or molecules are excited. Spontaneous emission from atoms (or molecules) excited by some means other than heating is called luminescence. There are different forms of luminescence depending on how excited atoms are produced (electroluminescence, chemiluminescence, and so forth).
When the excitation involves the absorption of radiation, the spontaneous emission is fluorescence. You have phosphorescence when molecules have a metastable level and continue to fluoresce after the exciting radiation is removed.
The phase of the photon in spontaneous emission is random as is the direction in which the photon propagates.
The explanation of why spontaneous emission happens gets to be quite complicated. Physicists had to devise what’s called quantum field theory and quantum electrodynamics to show why spontaneous energy transitions can happen.
However, measuring the result of spontaneous emission is straightforward. Light meters — and more specifically, photodiodes — are the main tools for quantifying light emissions from ordinary sources.
Spontaneous emission leads to the definition of stimulated emission. Lasers start via spontaneous emission, then transition to continuous operation by stimulated emission. Stimulated emission refers to a process where an electron interacts with an incoming electromagnetic wave in the form of a photon. The electron drops to a lower energy level, but in so doing it transfers energy to the incoming field. This action creates a photon having the same phase, frequency, polarization, and direction of travel as the photons coming in. Thus the photon emission is stimulated by the action of another incoming photon.
mark as a brainliest