Two Slit Interference Experiment Variations

In summary, various two slit interference experiments have been conducted to test the principles of Quantum Mechanics. These experiments involve measurements under special conditions such as light intensity, timing of irradiations, and polarizations. Some interesting experiments include the first double slit experiment of electrons done one by one, as well as Young's interference experiment with single photons. These experiments tend to support the principles of Quantum Mechanics, as they have shown interference patterns even with only one photon present in the apparatus. Further research and collection of references on these experiments would be useful in understanding the behavior of particles at the quantum level.
  • #1
Chas Tennis
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TL;DR Summary
Many two slit experiments were done to test Quantum Mechanics.
Some two slit interference experiments involve measurements under special circumstances of light intensity, timing of irradiations, polarizations, etc. For example, for light intensity where only one photon is in the apparatus, interference was observed. A collection of references to these various interesting experiments would be useful.
Examples that have references to special two slit experiments :
https://sciencedemonstrations.fas.harvard.edu/presentations/single-photon-interference

https://en.wikipedia.org/wiki/Double-slit_experiment

If you have an opinion on what you think the experiments tend to support and what they do not tend to support, please comment.

From the 1st example above,
"Comments:
Strictly speaking, we are not detecting single photons of light but rather single photoelectrons, liberated by the light impinging on the CCD.
......."

Note: searching with Google Scholar is very helpful.

Please post references.
 
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  • #3
anuttarasammyak said:
AFAIK the video in website https://www.hitachi.com/rd/research/materials/quantum/doubleslit/index.html
is the first double slit experiment of electrons done one by one. I love it.
Nature Scientific Reports -

Google Search title and the full publication is available.

Interference experiment with asymmetric double slit by using1.2-MV field emission transmission electron microscope.

Ken Harada1,3, Tetsuya Akashi2,4, Kodai Niitsu 1, Keiko Shimada1, Yoshimasa A. Ono1,Daisuke Shindo1,5, Hiroyuki Shinada2 & Shigeo Mori3

Abstract
Advanced electron microscopy technologies have made it possible to perform precise double-slit interference experiments. We used a 1.2-MV field emission electron microscope providing coherent electron waves and a direct detection camera system enabling single-electron detections at a sub-second exposure time. We developed a method to perform the interference experiment by using an asymmetric double-slit fabricated by a focused ion beam instrument and by operating the microscope under a “pre-Fraunhofer” condition, different from the Fraunhofer condition of conventional double-slit experiments. Here, pre-Fraunhofer condition means that each single-slit observation was performed under the Fraunhofer condition, while the double-slit observations were performed under the Fresnel condition. The interference experiments with each single slit and with the asymmetric double slit were carried out under two different electron dose conditions: high-dose for calculation of electron probability distribution and low-dose for each single electron distribution. Finally, we exemplified the distribution of single electrons by color-coding according to the above three types of experiments as a composite image.
 
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  • #4
I find another early demonstration on photon.

Young's interference experiment with single photons (Hamamatsu Photonics, 1982)

 
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  • #5
Chas Tennis said:
TL;DR Summary: Many two slit experiments were done to test Quantum Mechanics.
Some two slit interference experiments involve measurements under special circumstances of light intensity, timing of irradiations, polarizations, etc. For example, for light intensity where only one photon is in the apparatus, interference was observed. A collection of references to these various interesting experiments would be useful.

Examples that have references to special two slit experiments :
https://sciencedemonstrations.fas.harvard.edu/presentations/single-photon-interference

https://en.wikipedia.org/wiki/Double-slit_experiment

If you have an opinion on what you think the experiments tend to support and what they do not tend to support, please comment.

From the 1st example above,
"Comments:
Strictly speaking, we are not detecting single photons of light but rather single photoelectrons, liberated by the light impinging on the CCD.
......."

Note: searching with Google Scholar is very helpful.

Please post references.

Publication from the OP reference.

Young’s double-slit experiment with single photons and quantum eraser

Wolfgang Rueckner and Joseph Peidle
Harvard University, Cambridge, Massachusetts 02138(Received 25 January 2012; accepted 19 August 2013)

Abstract
An apparatus for a double-slit interference experiment in the single-photon regime is described. The apparatus includes a which-path marker that destroys the interference as well as a quantum eraser that restores it. We present data taken with several light sources, coherent and incoherent and discuss the efficacy of these as sources of single photons. VC 2013 American Association of Physics Teachers.

https://sciencedemonstrations.fas.h...-demonstrations/files/single_photon_paper.pdf
 

FAQ: Two Slit Interference Experiment Variations

1. What is the basic principle behind the Two Slit Interference Experiment?

The basic principle behind the Two Slit Interference Experiment is wave interference. When a coherent light source, such as a laser, passes through two closely spaced slits, the light waves emanating from the slits interfere with each other. This interference can be constructive (bright fringes) or destructive (dark fringes), creating an interference pattern on a screen placed behind the slits. This experiment demonstrates the wave nature of light.

2. How does the variation of slit width affect the interference pattern?

When the width of the slits is varied, it affects the diffraction of the light waves passing through them. Narrower slits cause more significant diffraction, leading to broader and less defined interference fringes. Conversely, wider slits result in less diffraction and sharper, more defined fringes. The overall visibility and spacing of the interference pattern are influenced by the slit width.

3. What happens if the distance between the slits is changed?

Changing the distance between the slits affects the spacing of the interference fringes. If the slits are moved closer together, the fringes become wider apart. Conversely, increasing the distance between the slits results in fringes that are closer together. This relationship is due to the change in the path difference between the light waves emanating from the two slits.

4. Can the Two Slit Interference Experiment be performed with particles other than photons?

Yes, the Two Slit Interference Experiment can be performed with particles other than photons, such as electrons, neutrons, and even larger molecules. When particles exhibit wave-like behavior, they also produce an interference pattern, demonstrating the principle of wave-particle duality. This phenomenon is a cornerstone of quantum mechanics.

5. How does introducing a detector at the slits affect the interference pattern?

Introducing a detector at the slits to determine which slit a photon or particle passes through collapses the wave function, resulting in the loss of the interference pattern. This is because the act of measurement forces the system to choose a definite state, which eliminates the superposition of states necessary for interference. This phenomenon highlights the role of the observer in quantum mechanics.

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