Single Photon Interference
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers, especially anna v, point people to it as a clear demonstration that single photons still build up an interference pattern.
Recommended by 2 people across 5 different months, 2013 to 2023.
What it is
A six-minute Veritasium video that revisits Young's double slit experiment with single photons, using a photomultiplier tube to count individual photon arrivals. After about two minutes it shows the interference pattern building up one photon at a time.
What people said
Recommends anna v · 2013-07 · Physics Stack Exchange · on “Double Slit experiment with just one photon or electron”
Yes, several people have done the experiment, and the photons/ [this video] electrons are not split, you can get one hit at a time. Here is a second video [LINK] . The wikipedia two slit article has a build up of the electron interference pattern one at a time. It is a probability pattern that shows the interference. The electrons and photons either go through one of the slits or the other, whole. Nothing mysterious is happening. There have been experiments recently where one can detect which the slit the particle went through [LINK] and still the interference pattern appears.
Recommends anna v · 2014-03 · Physics Stack Exchange · on “How does one detect a single photon?”
The photons are not detected at the slits. They are detected at a distance from the slits as illustrated here: [LINK] Photons or particles of matter [LINK] (like an electron) produce a wave pattern when two slits are used This has been done with single photons, as seen in this video. [this video] (after 2' it shows single photon interference), and this publication. [LINK] . The detector of single photons in the video is a photomultiplier [LINK] at the screen position. Generally if a detector is put in one slit, the interference disappears. Here is [LINK] the build up of single electron interference Successively longer integration times as electron arrivals (white dots) are recorded. There have be
Recommends user6972 · 2014-05 · Physics Stack Exchange · on “Double slit experiment and single particles. Is the wave function just a mathematical model?”
The fact that a photon can interfere with itself is counter-intuitive. Here is the single photon experiment for you to see [this video]
Recommends anna v · 2014-09 · Physics Stack Exchange · on “How do you isolate a single photon?”
This is an instructive video [this video] on the double slit experiment with photons which is experimenting with single photons. At about 2.5 minutes it explains how the experiment is done with single photons. In a nutshell, by lowering the intensity of a light source to the point of zero emitted by the source and then slowly increasing it. The detection hinges on the detector of single photons, in this case a photo multiplier. Photo multipliers work by multiplying the input from a single hit into an avalanche that is detectable electronically. For this detector since it has not been isolated from cosmic rays a noise background exists. If one googles "single photon detectors" a number of commerci
Recommends anna v · 2017-10 · Physics Stack Exchange · on “Can people create single photon in the laboratory?”
This double slit experiment [LINK] uses single photons. [LINK] In 2003, A. Weis and R. Wynands at the University of Bonn (Germany) designed a lecture demonstration experiment of single photon interference from a double slit. Light from a laser pointer was so strongly attenuated that at each instant there was only a single photon between the double slit and the detector. The diffracted light was recorded by a single photon imaging camera consisting of an image intensifier (multichannel plate, MCP) followed by phosphor screen and a CCD camera. When adding consecutive camera frames one sees the gradual appearance of the smooth classical interference pattern Each dot is the footprint of a single
Cites anna v · 2013-07 · Physics Stack Exchange · on “Photons-Wave/particle duality”
The two resulting rays are said to constructively interfere, which is confusing to me. The two rays are clearly parallel, but not coinciding, so how do the two interfere at all? You are actually confusing three different physics representations of the behavior of light, each framework self consistent and smoothly transitioning to the other in the region of validity. There is the classical electromagnetic wave framework, where light is an electromagnetic wave whose amplitude are changing electric and magnetic fields as the wavefront progresses. Rays are a geometric representation of the way the classical wavefront [LINK] progresses and transmits its energy and are useful for construction of o
Cites anna v · 2014-01 · Physics Stack Exchange · on “How far does a Photon's field Extend?”
One has to have clear that the terminology "photon" describes an elementary particle [LINK] . Elementary particles are described concisely in the framework of quantum mechanics. In this framework an elementary particle, the photon in this case, can have two behaviors. Either as a classical physics point particle with an x, y,z position , i.e. no extent in space, or as a probability wave , which means that a statistical accumulation of individual photons from the same starting conditions will display an interference pattern [this video] as a classical wave would. In the wave manifestation the extent of the locus where the photon may be found is bounded by the Heisenberg Uncertainty Principle [LINK
Cites anna v · 2014-06 · Physics Stack Exchange · on “New version of double-slit experiment”
Single photon experiments have been done [this video] . A more expensive experiment ( vacuum etc) . I think you will just blur the interference if you move the slits, due to the geometry angular changes.
Cites anna v · 2014-08 · Physics Stack Exchange · on “What exactly is Electromagnetic Radiation?”
There exists a very good formulation in this blog entry of Lubios Motl on how classical fields emerge from quantum theory, [LINK] . The link between the quantized photons and the classical field are the Maxwell equations , Classical solutions of the equations give rise to the classical fields. Used with the operator formalism the wavefunction describes a photon. The square of the wavefunction gives the probability of finding the photon at (x,yz,t). It carries not only the frequency nu of the classical field in its energy E=h*nu but also phases connected with the classical vector electromagnetic potential. In a handwaving sense, the classical field is not chopped up into photons, but it emerg
Cites anna v · 2014-09 · Physics Stack Exchange · on “Can quanta have different energy levels?”
The energy of a wave is h*f. The energy in an electromagnetic wave is [LINK] where E is the electric field of the wave as it moves [LINK] with velocity c. How i imagine this is each cycle consisting of 1 quanta. There are no quanta in the sense you are imagining it. The classical wave above emerges from a zillion of quanta, called photons. For a classical wave of frequency f, the energy of each photon making up the wave is h*f but there are zillions of photons making up the wavefront. I sometimes hear people say the energy of a photon is equal to h*f That is correct. If you have a source of light of frequency f, and lower the intensity to the point of one photon at a time, that photon will h