Can Two Laser Beams Interfere with Each Other?

In summary, the conversation discusses the use of two low intensity lasers in a diffraction experiment and the issue of interference with photons from each laser. The conclusion is that the lasers must be coupled or synchronized in order to eliminate any information about which laser a photon comes from, making it similar to a single laser double-slit experiment.
  • #1
DParlevliet
161
2
I have a question about this old (closed) Thead about the quote:

"...but also two separate very low intensity laser beams have been sent through single slits to a common detector and a diffraction pattern resulted. The intensity was so low that the probability of a (semi-classical) photon being between the slits and the screen was close to zero." (from Oz)

I suppose two lasers don't each emit a photon at the same time. So if one photon is emitted by one laser (and not by the other laser) with which wave does the photon interfere?
 
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  • #2
My understanding is that in such an experiment, the two lasers have to be coupled or "locked" to each other in such a way that there is no information about which laser any individual photon comes from. This makes it analgous to a double-slit experiment with a single laser as a source, in which there is no information about which slit any individual photon passes through.
 
  • #3
Two lasers must be synchronizes to be sure that the photons has the same phase. But can lasers be locked that both also emit a photon at the same time?
 

1. How do laser beams interfere?

When two laser beams intersect, they create an interference pattern. This happens because the light waves from each beam either reinforce or cancel each other out, resulting in areas of bright and dark light. This is known as constructive and destructive interference, respectively.

2. What factors affect laser beam interference?

The interference pattern of laser beams can be affected by several factors, including the wavelength of the light, the angle at which the beams intersect, and the distance between the sources of the beams. Changes in these factors can alter the interference pattern and create different patterns.

3. Can laser beams interfere with each other at any angle?

No, laser beams can only interfere with each other at specific angles. This is because interference patterns are created when the light waves from each beam are in phase, meaning they are aligned and have the same wavelength. If the beams intersect at an angle where they are not in phase, no interference pattern will be created.

4. How is the interference pattern of laser beams used in science?

The interference pattern of laser beams has many practical applications in science. It is used in technologies such as holography, which creates 3D images using interference patterns, and interferometry, which measures very small changes in distance or wavelength. It is also used in experiments to study the properties of light and quantum mechanics.

5. Can laser beams interfere with each other in a vacuum?

Yes, laser beams can interfere with each other in a vacuum. The absence of air or other particles in a vacuum does not affect the interference pattern of laser beams. However, interference can be affected by the medium through which the light travels, such as water or glass, due to changes in the speed and direction of the light waves.

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