How does an emission take place by radiation?

In summary, when an electromagnetic wave hits a semiconductor, the perturbed Hamiltonian takes into account the vector potential and adds two terms to the unperturbed Hamiltonian, one for absorption and one for emission. The common belief is that the incident radiation is absorbed and then a new photon is radiated. However, this is just a model and there could be a range of possibilities if not directly measured. If there are already excited electrons present, the incoming radiation can cause them to decay through stimulated emission. This process is known as "stimulated emission" and can be further researched.
  • #1
hokhani
483
8
When an electromagnetic wave is impinged on a semiconductor and we solve the perturbed Hamiltonian by taking into account the vector potential in the momentum term, two terms would add to the unperturbed Hamiltonian which one of them deals with absorption while the other with emission. I like to know whether the emission is made by the incident radiation itself, or first the radiation is absorbed then the excited electron would come back and radiate?
 
Physics news on Phys.org
  • #2
The usual picture is that a photon gets absorbed and then another photon is radiated.

Careful though, a model need not follow the physical process.
If you have not measured it, then there may be a range of things that could have happened.
 
  • #3
Simon Bridge said:
The usual picture is that a photon gets absorbed and then another photon is radiated.
If we have some electrons at higher levels before impinging, would they come down to the lower levels by emission after impinging? (Suppose that we have only two possible ways, absorption and emission by electrons)? Or first the photon is absorbed by an electron and then emission is only made by the excited electron when is coming back to lower levels?
 
  • #4
Sure - if you have already excited electrons, the incoming radiation can prompt them to decay.
The process is called "stimulated emmission" ... you can look it up ;)
 
  • Like
Likes 1 person

1. What is an emission by radiation?

An emission by radiation is the process by which energy is released in the form of electromagnetic waves or particles. This energy can come from various sources such as atoms, molecules, or other particles.

2. How does an emission by radiation occur?

An emission by radiation occurs when an atom or molecule in an excited state releases energy in the form of photons. This can happen spontaneously or as a result of an external stimulus, such as heat or electricity.

3. What types of radiation are involved in an emission?

The types of radiation involved in an emission can include visible light, infrared radiation, ultraviolet radiation, X-rays, and gamma rays. The specific type of radiation emitted depends on the energy level of the emitting particle.

4. What factors affect the rate of emission by radiation?

The rate of emission by radiation can be affected by several factors, including the temperature of the emitting particle, the type of material, and the presence of external stimuli. For example, higher temperatures typically result in a higher rate of emission.

5. How is an emission by radiation important in everyday life?

Emission by radiation plays a crucial role in various everyday processes, such as cooking, heating, and producing electricity. It is also essential in technologies such as medical imaging, communication systems, and renewable energy sources like solar panels.

Similar threads

I Radiative and Nonradiative Transitions
    • Atomic and Condensed Matter
Replies
3
Views
2K
I How do emissivity and absorptivity affect thermal imaging results?"
    • Thermodynamics
Replies
3
Views
331
I Why don't absorption and emission spectra "cancel out"?
    • Atomic and Condensed Matter
Replies
8
Views
2K
I Effective molecular Hamiltonian and Hund cases
    • Atomic and Condensed Matter
5
Replies
156
Views
7K
I Assumptions for blackbody spectra vs. emission spectra vs. absorption spectra
    • Astronomy and Astrophysics
Replies
8
Views
2K
I Planck Emission Spectrum
    • Quantum Physics
Replies
23
Views
2K
B Radiation detector types/physics
    • High Energy, Nuclear, Particle Physics
Replies
24
Views
2K
I Are all processes CPT symmetric like measurement, stimulated emission?
    • Quantum Physics
Replies
8
Views
818
Localized absorption of photons and carrier generation
    • Atomic and Condensed Matter
Replies
3
Views
2K
A Kinnersley’s “photon rocket” and gravitational radiation
    • Special and General Relativity
Replies
14
Views
2K

Hot Threads

Recent Insights

Back
Top