Hi all,
It is supposed that we have the following experiment:
A laser emitting monochromatic light placed in front of a double Young's slit and a screen is placed at a given distance behind the double slit. Another laser of the same wavelength is placed perpendicularly to the first laser at the half distance separating the first laser to the double Young's slit. My question: is there a non-negligible probability for the process photon-photon interaction, if so, how it can affected the expected results (wave pattern) as shown in an usual photon double sit experiment.
Thanks,
Jaafar
It would be ideal to try the experiment to see what happens but my expectation is that the photons passing through the dual slits to the detector would not be affected by photons passing in a direction perpendicular to the dual slit apparatus.
The reason for this can be explained by thinking of the photon as a wave quantum rather than as a particle which could collide:
Conference Paper THE UNIFICATION OF PHYSICS
Data Prerecording of Conference Presentation on the Unification of Physics
Richard
In typical intensities two laser beams don't effect each other, or may be their effect on each other is not measurable(very very small). I performed an experiment similar to your question and no interaction observed. I am not sure about observing same result In very high intensities(nonlinear optics range), but I think there is no interaction.
Thank you Richard Lewis for your reply, Yes I agree with you, as photon emitted by the first laser is treated as wave it should not probably interact with one emitted perpendicularly by the second laser. But what can be expected according to the modern physics, when we keep photon moving more slowly, for example by inserting a material with special properties between two lasers and double Young's slit, that prevents photon to go back to its usual velocity when it leaves this bremsen material (it should not be water or glass because photon will return back to C in a free space). The idea is to make a photon think that its being a particle more than a wave, in order to increase the cross-section of photon-photon interaction.
Thank you Abbas Majidi Bidgoli for your reply.
I think, probably, their effect on each other is not measurable with technology that we have to this day, do to the too small mass of photon < 10-54 kg and then small cross section too.
Thank you for sharing the results of a similar proposed experiment.
Your post illustrates the problem that we all have with wave / particle duality. The concept of wave / particle duality implies that a photon or an electron is sometimes a wave and sometimes a particle. This is most unsatisfactory as we would like it to be just one thing and understand what that one thing really is. This is why I have settled on the description of the photon as being a wave quantum. That is a wave disturbance of spacetime with a specific energy given by E = hf. Light is quantised in this way because that is the way it is emitted not because of some inherent property of light.
So I do think the interference experiment is a very revealing choice to understand what is really going on with these wave quanta, which is why I mentioned it specifically in the video:
Data Prerecording of Conference Presentation on the Unification of Physics
I see what you are trying to do when you say "make it think it is being more like a particle" but it really is a wave. Now the problem of understanding how waves interact is a bit difficult to predict.
For example, there is an experiment which fires laser pulses at a hydrogen atom to try to establish the position of the electron. This experiment is designed in such a way that it knocks the electron out of the atom and then detects its trajectory so drawing conclusions about the electron's original position. The result that you get when you run this experiment many times is the predicted probability cloud for the electron around the nucleus. So you go away with the idea that the electron is a particle with a probability wave around the nucleus.
But really what is happening is that the electron is a looped wave in spacetime (see video link above) and when it interacts with the laser pulse ( a non-looped wave disturbance of spacetime), the effect is to knock the electron out of the atom and into the detector system which will always give the result of a particular point in space even though the interaction was between waves.
So in your example between photons and photons we do have an interaction between waves and it is quite hard to predict the outcome of the experiment that you propose. Best thing would be for someone to try the experiment.
Richard
Thank you Richard Lewis for your exquisite and detailed explanation, I am going to watch the concerned video and also the concerned paper.
Yes of course the best thing to do is to make an idea on the ground. I will try the experiment as soon as possible.
Jaafar
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