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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What happens to the energy when waves perfectly cancel each other?

What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be ...
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5answers
5k views

Does a photon interfere only with itself?

I sometimes hear statements like that: Quantum-mechanically, interference pattern occurs due to quantum interference of wavefunction of a photon. Wavefunction of a single photon only interferes ...
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5answers
9k views

Interference of polarized light

Does polarized light interfere?
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1answer
197 views

Relationship between the material properties of an edge and the fringes behind this edge

The double-slit experiment shows fringes on a screen. Closing one of the slits there is still an interference pattern on the screen behind the slit. Making the slit wider we still see fringes between ...
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3answers
4k views

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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4answers
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Energy conservation and interference

I have a problem with energy conservation in case of interfering waves. Imagine two harmonic waves with amplitudes $A$. They both carry energy that is proportional to $A^2$, so the total energy is ...
9
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2answers
485 views

Fully destructive interference

I'm aware that this is somewhat of a frequently asked question (not only here), and i've dug through respective answer for a few hours before i decided to ask here. None of those answers helped me ...
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3answers
856 views

Recently publicized experiment on destructive interference between two laser beams

Recently I've had several non-physicist friends ask me, independently of each other, about an experiment where two collinear laser beams destructively interfere along a certain length. Everybody wants ...
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5answers
604 views

Are double-slit patterns really due to wave-like interference?

According to various sources on the web, it seems like the general concensus is that there isn't actually any wave-particle duality with quantum particles. For example, this article implies that ...
126
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7answers
10k views

Stupid yet tricky question: Why do we actually see the sun?

I haven't yet gotten a good answer to this: If you have two rays of light of the same wavelength and polarization (just to make it simple for now, but it easily generalizes to any range and all ...
12
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6answers
4k views

How come an anti-reflective coating makes glass *more* transparent?

The book I'm reading about optics says that an anti-reflective film applied on glass* makes the glass more transparent, because the air→film and film→glass reflected waves (originated from a paraxial ...
12
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4answers
961 views

How does interference move energy from destructive to constructive regions?

I recently read (sorry but I don’t have a reference) that interference is not only about destructive and constructive interference but moving energy from destructive to constructive regions according ...
10
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5answers
11k views

Is coherent light required for interference in Young's double slit experiment?

In this Veritasium video, a home experiment is presented which appears to produce a very good double-slit interference pattern with normal sunlight. The experiment is an empty cardboard box with a ...
5
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2answers
797 views

How does light know which path is fastest?

We know from Fermat's principle of least time that light follows the fastest path. But how does light know which path is the fastest?
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2answers
1k views

Does diffraction occur before interference?

In the double slit experiment, light passes through two slits and the waves interfere and form an interference pattern. A single slit is required for diffraction. So, I was thinking about whether ...
3
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3answers
465 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 ...
2
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1answer
658 views

Diffracton at the edges of an opaque object?

To understand the phenomenon of diffraction as an interference effects of several dipole oscillators (like in case of several symmetrical, not sawtooth, scratches in a diffraction grating), we ...
2
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1answer
8k views

How to calculate the intensity of the interference of two waves in a given point? [closed]

There are two different point sources which produce spherical waves with the same power, amplitude, ω, wavenumber and phase. I can calculate the intensity of each wave in a point: $$ I_1 = P / (4 ...
2
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4answers
3k views

Single photon and double-slit experiment [duplicate]

Laser fires single particles of light, called photons, through the slits. Even though only single photons of light are being fired through the slits and They create three pattern again. How single ...
5
votes
1answer
7k views

Purple doesn't occur in rainbow - or does it?

Usually, when asked whether the purple color exists rainbows, an answer similar to this is given: The purple color is perceived by human eyes via the activation of both red-sensitive and ...
2
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1answer
59 views

Interference and energy question here

So Im reading this material on interference and I noted the following sentence : During the interference of the light of two coherent light sources,the intensity of the radiation changes ...
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1answer
132 views

Period of Interference Pattern on a Substrate

Can anybody explain to me where this equation came from? It's for two point sources at the two listed points, and it's calculating the period of the wave on the substrate. It seems to be ...
0
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2answers
2k views

Does wave interference happen only to same frequency waves?

As the title says, from books and results from internet, I find that examples of wave interference always have the same frequency, only different in phase constant. So, I'd like to know if wave ...
6
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4answers
20k views

Difference Between Fraunhofer and Fresnel Diffraction

What is the difference between Fraunhofer diffraction and Fresnel diffraction? I mean diffraction is just bending of light waves or waves in general around a point. So how can there be two types of ...
21
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4answers
5k views

How much red, blue and green does white light have?

Different kinds of white light have a different spectrum. Light from a white LED will have blue at the peak intensity while white light from a CFL or something else will have a different looking ...
8
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6answers
3k views

Why does a wave actually diffract?

I know that waves diffract around a slit and this is due to the Huygens-Fresnel principle. But I never understand this in an intuitive wave that why does a wave become a spherical wave front at the ...
5
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2answers
1k views

is a single photon a wave? Is it a wave packet?

How could it split and interfere? How could a wave packet, with many frequencies, be a photon with one freq.? Thank you very much.
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3answers
3k views

Why does light in a room not form constructive and destructive interference patterns?

This is something that I have wondered for a long time. How come when I walk around why do I not see random black spots where light has collided destructively and bright spots where it has collided ...
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3answers
659 views

Experiment demonstrating interference patterns of neutrons

The question is about experiments (and references) that demonstrate interference patterns of neutral (chargless) particles (fermions), especially neutrons. Like double-slit experiments for neutrons ...
10
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2answers
276 views

How can laser interferometry be used to measure path difference smaller than wavelength of laser light?

The currently proposed Gravitational wave detection apparatus consists of Michelson Interferometer which is supposed to measure distances of the order of $10^{-22}$m. But the wavelength of the light ...
9
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2answers
6k views

Where does energy go in destructive interference? [duplicate]

I have read that when two light waves interfere destructively, the energy contained within is transferred to other parts of the wave which have interfered constructively. However, I am having some ...
3
votes
4answers
90 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 ...
1
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5answers
161 views

Single Photon Single Slit Interferometry

If just a single photon hit a single slit interferometer, what would happen? Would you just see a dot on the screen, or would there be a diffraction pattern? Furthermore, if you had a double slit ...
2
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2answers
756 views

Interference at the focus of a convex lens or a concave mirror

Now consider parallel rays travelling towards the convex lens. After emerging they get converged at the focus. Won't this lead to interference between light rays? Practically it should but I would ...
2
votes
2answers
1k views

Can we observe diffraction even if the slit size is tending to zero?

According to Huygens principle, if we consider any point of the primary wave fronts, each point is the source of secondary disturbance. If the point size we consider tends to zero, the number of ...
1
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1answer
47 views

Physical understanding of Anderson (disorder) localisation

My current understanding is that waves in disordered potentials experience localisation due to interference effects. (eg an electron in a disordered medium tries to take different paths of effectively ...
42
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7answers
6k views

Why don't two musical instruments sometimes generate destructive interference?

I'm an electrical engineer, and I understand wave propagation, interference patterns, and so on. But I'm missing something basic, so perhaps my understanding isn't as good as I believe. I'll show my ...
11
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5answers
913 views

Double slit experiment near event horizon

What happens if you perform a double slit experiment near an event horizon, if one of the slits is outside, one is inside the event horizon?
9
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1answer
1k views

Why does my body create interference with my clock radio while in bed?

I typically listen to NPR in the morning from a clock radio next to my bed. There are days when just moving my body, even my arm or leg, is enough to cause interference with the radio to dramatically ...
7
votes
3answers
622 views

Which is the biggest object which can interfere with itself?

I've heard that scientist proof that viruses of the Tobacco mosaic virus could interfere with themselves. I'm referring to quantum interference-- the same as photons. Unfortunately, I couldn't find ...
3
votes
1answer
427 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 ...
2
votes
1answer
75 views

how can interference occur within diffraction?

My book says : The number of interference fringes occuring in the broad diffraction peak depends on the ratio d/a that is the ratio of the distance between the two slits to the width of a slit. In ...
3
votes
2answers
72 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 ...
2
votes
1answer
180 views

Ring Resonators

If optical field will propagate into the following ring resonator. Optical field will propagate into the ring and propagate to the coupling region. I didn't get where and how the interference will ...
1
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2answers
399 views

Intuitive explanation of the waves superposition

When the two waves collide, why do they pass right through each other? Mathematically it's due to the principle of superposition: the sum of the two solutions of a wave equation is also a solution. ...
0
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2answers
128 views

multiverse fabric of reality

Source-"fabric of reality"- author d. deutsch - his contention, as I understand it, is that quantum interference is caused by "almost, but not identical quite quantum entities" , e.g. electrons, from ...
6
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3answers
3k views

Do laser beams interfere noticeably with each other?

I want to arrange some red lasers along a 90 degree arc of a circle, aimed towards the center of the circle. When their beams hit the opposite side of the circle, will I notice any interference ...
5
votes
3answers
132 views

Wave or particle in the end

In Young's double slit experiment I put a convex lens after double slit and direct interference pattern on to a fibre. Then I expose the other end of fibre to a screen. What will I observe - the ...
4
votes
4answers
139 views

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 ...
3
votes
2answers
46 views

Introducing a phase, what changes?

This question is related to: Mach-Zehnder interferometer and the Fresnel-Arago laws Let us say we have unpolarised wave taking the form: $$\psi=\psi_0 e^{i(kx-\omega t)+i\phi(t)}$$ Where $\phi$ ...