Absorption of 2 photon by 1 electron in photoelectric effect

In summary, the photoelectric effect is a phenomenon in which a photon strikes an electron in a material, causing it to be ejected. 2-photon absorption occurs when two photons with a combined energy greater than the binding energy of the electron are absorbed simultaneously, resulting in the electron being ejected with increased energy. This is significant because it allows for the absorption of lower energy photons and materials with lower work functions can still exhibit the photoelectric effect. The energy of the ejected electron is increased in 2-photon absorption and it can occur with any material that exhibits the photoelectric effect. 2-photon absorption has various applications in modern technology, including medical imaging, microscopy, laser technology, and solar cell efficiency improvement.
  • #1
spaghetti3451
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Homework Statement



In the photoelectric effect, it is assumed that a single electron absorbs a single photon. But, there is a certain probability that a single electron may simultaneously absorb two identical photons from a high-intensity laser. How would such an occurrence affect the threshold frequency, the stopping potential and the equation ## eV_{0} = hf-\phi ##?

Homework Equations

The Attempt at a Solution



The threshold frequency is halved because it is possible to have the most loosely bound electron (with binding energy = work function) absorb the two photons.

The equation ## eV_{0} = hf-\phi ## is modified to become ## eV_{0} = 2hf-\phi ## because hf is the energy of one photon.

Therefore, the stopping potential for a given frequency increases from its corresponding earlier value.Are my answers correct?
 
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  • #2
The threshold frequency of any metal on which monochromatic electromagnetic radiation which causes two photon absorption(or interaction) is incident will be half the value of what it would normally be for single photon interactions, which you have correctly evaluated. So the equation ##h(f-f_0) = \frac{1}{2}m_e v^2 = e V_0## becomes equal to ##h(2f-f_0)## where ##f_0 = 2 f_x ## (fx is the threshold frequency for the TPA effect), which is essentially the same as the last equation you came down to in the end. So yes, for E.M. waves with the same frequency, with the TPA effect, you will have a higher stopping potential value.(The ratio of the stopping potentials will be ##\frac{2f-f_0}{f-f_0}## to be precise).
P.S. Let me know if you think there's somewhere I went wrong.
 
  • #3
Might I add that if there are ##n## photons with distinct energies (##n## frequencies) in a mixed frequency E.M. wave and, hypothetically speaking, if all of them could simultaneously interact with one electron, then the stopping potential would be given by ##eV_0 = h(f_1+f_2+f_3...+f_n -f_0)## , where photoelectric emission just starts happening when ##f_0 = ∑f_i##. The ratio of stopping potentials in this case would be ##\frac{∑f_i - f_0}{f_x-f_0}## where ##f_x## is the frequency of the monochromatic E.M. wave with which we are comparing the mixed frequency wave with. (##f_i## is the set of frequencies in the mixed frequency E.M. wave). I really hope I'm not over-complicating this o0)
 

1. How does the absorption of 2 photons by 1 electron in the photoelectric effect work?

The photoelectric effect occurs when a photon (a particle of light) strikes an electron in a material, causing the electron to be ejected. In the case of 2-photon absorption, two photons with a combined energy equal to or greater than the binding energy of the electron are absorbed simultaneously, causing the electron to be ejected with increased energy.

2. What is the significance of 2-photon absorption in the photoelectric effect?

2-photon absorption is significant because it allows for the absorption of photons with lower energies than the binding energy of the electron. This means that materials with lower work functions (the amount of energy needed to eject an electron) can still exhibit the photoelectric effect.

3. How is the energy of the ejected electron affected by 2-photon absorption?

The energy of the ejected electron is increased when 2 photons are absorbed simultaneously. This is because the total energy of the two photons combined is greater than the binding energy of the electron, resulting in the electron being ejected with more energy.

4. Can 2-photon absorption occur with any type of material?

2-photon absorption can occur with any material that exhibits the photoelectric effect. However, certain materials may have a higher probability of 2-photon absorption due to their electronic structure and energy levels.

5. What applications does 2-photon absorption have in modern technology?

2-photon absorption is currently being researched and utilized in various technologies such as medical imaging, microscopy, and laser technology. It has also been proposed as a potential method for improving solar cell efficiency.

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