Interference describes different waves superposing to form a resultant wave of greater, lower, or the same amplitude. Normally, it involves interaction of waves that are correlated (coherent) with each other, either because they come from the same source, or because they have the same or nearly the ...

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Will overlapping two different beams of coherent light cause interference?

I have two laser beams with same polarization running parallel to each other. Will they interfere? If yes, then what are the conditions (perpendicular distance etc) and how can I observe the ...
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835 views

Does thin film interference (anti-reflective coating) let more light through?

The theory of an anti-reflective coating is that the reflected light off the coating and the reflected light off the substrate is 180 degrees out of phase, causing destructive interference and ...
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reproducing double-slit experiment with sunlight

Is it possible to reproduce Double-slit experiment at home with sunlight probably in a larger scale? Thanks for all the answers (and special thanks to Chris for the effort),so i understand that it ...
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108 views

Is diffraction through an aperture similar to diffraction by a plane of atoms?

I'm asking because I have a problem asking me what the diffraction pattern would be if instead of spherical atoms I'd have triangular atoms. I can't find anything about this in my X-ray diffraction ...
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Young's double-slit experiment with detectors

Related: Accuracy of various optical instruments In many books, it's written that knowing which slit a photon passes through (by placing a detector before the slit) in a Young's double-slit setup ...
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How was Fizeau able to measure interference fringes in his experiment of 1851?

I am wondering how Fizeau, in the famous experiment of 1851, was able to measure changes int the interference fringes given that he used Sun light. Sun light constists of all kinds of wave lengths ...
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What is three-photon interference?

Whilst reading this paper on a quantum processor that performs a type of matrix computation, I came across the concept of 'three-photon interference'. A quick Google search shows that this process is ...
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What is the difference between diffraction and interference of light? [duplicate]

I know these two phenomena but I want to know a little deep explanation. What type of fringes are obtained in these phenomena?
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Why is it difficult to differentiate between interference and diffraction?

Why is it difficult to differentiate between interference and diffraction? Is it because we don't clearly understand how both of these phenomenon takes place? My thoughts: From an answer to one of ...
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2-slit experiment

In the 2-slit experiment, is it possible to "account" for all of the energy in the incoming beam - i.e. does all of the incoming energy show up in the bright spots or is some of it "destroyed" when ...
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318 views

How to interpret single photon interference when the two possible paths are different in length?

Here is my question. I struggle with the definition of single photon interference. Let’s assume we have a Michelson interferometer and the interference pattern we observe is a single photon result, ...
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161 views

Covering centeremost slit of a N slit diffraction grating - what happens?

For an N-slit diffraction grating, the distance from a maxima to a minima at order p is given by $$\delta \theta = \frac{\lambda}{Np}$$ What happens to this width when the centremost $\frac{N}{2}$ ...
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How is the width of a slit related to the intensity of light passing through it?

Here's a question I got in my final exam this morning. "If in a Young's double slit experiment setup, the ratio of intensity of the bright spot to the dark spot is 25:9, what is the ratio of the width ...
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453 views

Do interference rings disappear in an interferometer if the path lengths are identical?

Consider a standard Michelson Interferometer (I took the picture from http://en.wikipedia.org/wiki/Interferometer) The incident beam is split into two parts, where the two parts travel on different ...
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62 views

Time-coherency of “incoherent” light

Even "incoherent" light as the one of a light bulb has some coherency, and would interfer in the double-slit experiment (even if more blurry because the different wavelengths don't trigger the same ...
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89 views

Wave interference

Visualizing the double slit experiment, there are light lines and dark lines. The dark lines I understand are caused by the interference cancelling waves. What I don't understand is where the energy ...
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334 views

Probability wave speed of dispersion and interference

I'm a layperson learning about quantum mechanics and probability waves. My understanding is that the probability wave for the position of a particle disperses throughout all of the universe. I have ...
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988 views

Why do I hear beats through headphones only at low frequencies?

I was recently playing with this Wolfram Demonstrations applet, which demonstrates beats. At first I thought the app didn't work because I couldn't hear any beats. Then I realized that the applet ...
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27 views

How do large interferometers work?

In very large Michelson interferometer a such as LIGO, how can we keep the two light paths at the exact same distance in order to avoid any unwanted and noisy fringes shift? When I used to make ...
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147 views

Diffraction pattern without a slit

A few weeks ago, I aimed a laser at a wire perpendicular and interestingly, I saw the diffraction pattern, like the picture below: Why is this happening? I mean, I don't have any slits and I'm ...
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277 views

Shooting a single photon through a double slit

Consider the image below. It shows a double slit experiment but with a single photon at a time. My question is as follows: Why is it that the photons always take a different path when shot at the ...
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1answer
116 views

How can I easily explain interference to a tour group?

I'm looking for unique and illustrative ways to explain the phenomenon of interference to a tour group consisting of all types of people, from elementary school kids to adults. I run into this ...
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465 views

Double-slit expirement fundamentals (half-silvered mirror version)

In the double-slit experiment variation in which 2 half-silvered mirrors and 2 mirrors are used to illustrate the interference of a stream of photons or single photons at a given time step, how is it ...
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Describing quantum intereference with only currents and densities

I know about and believe to understand the general wave equation based Kirchhoff diffraction formula, which in the Fraunhofer limit leads to a farfield complex wave function by Fourier transforming ...
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69 views

Diffraction pattern in one continuous slit

Will a noticeable diffraction pattern appear if I use a single continuous slit, say a ring shaped one?If yes, can it be explained how the slits were paired for interference observations , and is there ...
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Creating complex interference figures with simple sources

3D printers that use Stereolithography usually have to build a 3D object layer by layer, each layer being constructed by having a laser travel across the surface until it has hardened all the layer's ...
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142 views

How to check whether Schrödinger's cat was in superposition of states?

Suppose we can make an arbitrarily precise preparation of a Schrödinger's cat (and isolate it arbitrarily well so that decoherence is not a problem). If we prepare lots of cats in this state, what ...
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Mechanical pulse reflection

When we have a rope with one fixed end and we send a pulse through it, the reflected pulse is inverted. My question is as follows - is it correct to say that near the end (when the pulse hits the ...
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White light diffraction

I have a hard time understanding why light waves of different wavelengths diffract in a different manner. According to Huygens' principle, every point on the wavefront is a source of a secondary wave. ...
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590 views

Single photon interference experiment

In short: the question is, does the length of the path affect the outcome of detecting a photon? Consider the single photon beam splitter experiment. Does the probability of detecting the photon ...
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56 views

Loss of interference in single-photon Mach–Zehnder interferometer with detector in only one arm

I have read that if you have a Mach–Zehnder interferometer (doing a single-photon experiment) and put a non-destructive detector in only one of the two arms (connected to the first beam splitter), you ...
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3answers
73 views

What is the Difference Between Quantum and Classical Interference

I was reading about Quantum decoherence and I came across this quote, "decoherence has irreversibly converted quantum behaviour (additive probability amplitudes) to classical behaviour (additive ...
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410 views

Why doesn't a backward wave exist? [duplicate]

Huygens principle says every point of wavefront emit wavelet in all directions. Then why does a back ward wave not exist? Can any expert tell real answer? On different sites I get different and ...
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1answer
47 views

Interference of light in a dielectric mirror

Here it is mentioned that for dielectric mirrors (mirrors designed to reflect a specific wavelength of light) "there is a 180-degree difference in phase shift at a low-to-high index boundary, compared ...
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Thickness of thin-film interference [closed]

A thin film of alcohol ($n = 1.36$) lies on a flat glass plate ($n = 1.51$). When monochromatic light, whose wavelength can be changed, is incident normally, the intensity of the reflected light is a ...
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Fastest path of light [duplicate]

Fermat's principle of least time says that light always takes the fastest path to any point. So how can light know which is the fastest path without taking all the paths first?
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Can two single particles interfere with each other?

Groups of particles can interfere with one another; In the double slit experiment when measuring single photons at the screen each one arrives at the screen in a random manner and they only show the ...
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862 views

Questions about Michelson interferometer

I have been doing experiment on Michelson experiment, but I don't quite understand why white light results in an interferogram with very few fringes, and why are they necessarily Gaussian? I know that ...
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200 views

Period of double slit experiment

What is the period of the pattern from the double slit experiment? It varies along the pattern right? Namely I'm confused because when considering two point sources (See: Period of Interference ...
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487 views

A question on intereference experiment with water waves as given in the Feynman Lectures on Physics

I have a question related to the interference (thought)experiment with water waves given in the book Feynman Lectures on Physics Vol.3. When only one hole (hole 1) is open the measured wave intensity ...
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3answers
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What does the differential of $d_s\sin(\theta) = m\lambda$ help us see, with respect to waves through diffraction gratings?

With respect to waves traveling through a diffraction grating, we have an equation like this one: $$d_s\sin(\theta) = m\lambda.$$ Where $d_s$ is the distance between slits in the grating, $\theta$ is ...
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What's the reason double-slit experiment can't be explained by edge effects rather than quantum interference? [closed]

Say we had exactly this... But instead, it was a PING PONG GUN (imagine as table tennis players use to train), throwing out PING PONG BALLS. The two slits are say 20 cm wide, and the observing ...
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1answer
583 views

Wave superposition, is my textbook wrong?

Here's the question: Two coherent electromagnetic waves are incident simultaneously at some point in space. The intensity of each independent wave is $I_0$. What is the intensity of the superposition ...
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3answers
571 views

Does interference take place only in waves parallel to each other?

The title says it all but I will add some details. I believe that interference takes place only in waves which are parallel to each other. See the picture to understand what I mean by parallel. We ...
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3answers
112 views

Is wave superposition always equivalent to wave interference?

I'm confused when using these 2 words "wave superposition" and "wave interference" since their definition is very similar. So, are these 2 term the same?
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2answers
60 views

Where the extra power comes from?

Suppose we have two radio waveforms each has amplitude of 1, then the total power is 2. Suppose these two waveforms add up some where constructively, then the amplitude become 2, and the total power ...
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117 views

Interference conditions problem

We know that two wave sources can interfere if two sources have the same frequency two sources must have a constant phase difference over time. But I think that if condition 1 is satisfied, ...
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2answers
87 views

How is the virtual image reconstructed from a hologram?

To make a hologram a film is exposed to an incident plane wave and wave from the object to record the interference pattern on the film. The principle is commonly explained in a way like that in p.1212 ...
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182 views

Violation of conservation of energy?

Imagine a perfectly spherical mirror with 100% reflection. Imagine a point source of light in the center. The point source keeps radiating light. Will the light undergo destructive interference ...
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336 views

Thin-wedge Interference Problems (Classical Waves Problem)

I would like to solve the problem on the following image: My question is: Why is the answer to (a) a minimum? When the light wave hits the top surface of the top glass, a wave will be reflected ...