Questions tagged [interference]

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 same frequency. Interference effects can be observed with all types of waves, e.g., light, radio, acoustic, surface, or matter waves.

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Is This Quantum Eraser Video from Fermilab Incorrect?

In a video from Don Lincoln of Fermilab here, the following claim is made about a quantum eraser-type setup (about 2 min 50 sec in): "If A & B are turned off, you see a wave pattern. That ...
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Interference and conservation of energy in a resonator

It is known that constructive interference in one place must be compensated for by destructive interference in another. Take a simple Fabry Perot resonator for example. The interference occurring at ...
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Why Do We Ever Get Interference in a Quantum Eraser?

There are many questions on this site about the quantum eraser, but I think mine is not quite answered by any of the other answers on the topic. Here's the setup: My understanding of this experiment ...
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Degree of first-order coherence doesn't imply always 100% visibility?

In classic books of quantum optics visibility of interference fringes (for example in Michelson interferometer) is equal to the modulus of the degree of first order coherence $g^{(1)}$, when the ...
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Extreme sensitivity to the input scale of a Continuous Fourier Transform approximation from Discrete Fourier Transform

Is there a way to 'bypass' the condition $\Delta k=\frac{1}{x_{max}-x_{min}}$, which requires the range of $x$ to be very large when approximating the CFT encountered in Michealson Interometery as a ...
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Polarization of natural light for double slit interference

Last week I performed Young's double slit experiment using a laser. As expected, I obtained an interference pattern as predicted by Fraunhofer theory (enveloped by the 1 slit diffraction curve). Then, ...
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Why is wavefront quality important, and what is the relationship between the coherence length of a laser and its wavefront quality (if any)?

I am currently studying laser interferometry. I understand that the coherence length of a laser, $L_\text{coherence} = c T_\text{coh}$, where $c$ is the speed of light and $T_\text{coh}$ is the ...
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Is the double slit pattern a standing wave?

This question is about terminology. The double slit pattern has nodal lines and antinodal lines, and therefore resembles a standing wave. However, the antinodal lines within the double slit pattern ...
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Can electromagnetic waves with long wavelengths (1 kHz to 1 GHz) also be considered as Photons?

Could we conduct the Double Slit Experiment with long wavelengths (e.g. frequencies between 1 kHz and 1 GHz) and still measure through which slit the wave/particle goes? I am sure that the ...
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In Young's double slit experiment, do we observe fringes to a limit? [closed]

As fringes are observed due to diffraction at two sources and diffraction has a particular area to cover. So we should be getting fringes only upto certain distance?
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If a weak eigenstate (such as a $d'$ or a neutrino) interacts with a gravitational field do the mass eigenstates interact on their own?

Weak interaction eigenstates don't correspond with mass eigenstates. I was wondering how such a superposition of mass eigenstates would interact in a gravitational field. I assumed they would do so ...
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Thin Film Interference - longest wavelength of the light in water that is transmitted most easily [closed]

The problem: A scientist notices that an oil slick floating on water when viewed from above has many different colors reflecting off the surface, making it look rainbow-like. She aims a spectrometer ...
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Does intensity/amplitude of waves near coherent sources and near screen during interference experiment of light remain constant somehow?

Context of this question is based on high school level physics. As far as I could notice in many highschool textbooks, amplitude of the waves during interference are not changed in the region between ...
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Delayed Choice Quantum Eraser - what is seen on a screen placed at the main signal detector D0?

In the Delayed Choice Quantum Eraser experiment shown below, $D_0$ is a photon detector that is moved by a motor along the $x$-axis. What would be seen on a screen placed there?
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Is $I(\lambda)=I(\tilde{\nu})$ true in general in Fourier Optics?

Say the spectrum of a light bulb is given by $$I(\lambda)=I_0exp\left(-\frac{(\lambda-\lambda_0)^2}{2(\delta \lambda)^2}\right)$$ (i.e. a gaussian) if I want the intensity in terms of the wavenumber $\...
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Misconception with Fourier Transforms in a Gaussian Light source?

So for a Michaelson Interferometer , we know that the (complex) interferogram ($I=I(\Delta)$, $\Delta$=path difference between two mirrors) is related to the intensity profile of the light source $(...
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How to calculate the amplitude of the sum of two waves that have different amplitude? [closed]

I'm now trying to solve a problem like this. ($x$ denotes position and $t$ denotes time. $a_i, k, \omega, \delta_i$ are all constants.) Given the two waves, $u_1(x,t)=a_1 \sin (kx-\omega t + \...
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Why is there a single slit in the Young double-slit experiment? [duplicate]

I am studying waves these days and my teacher just introduced Young double-slit experiment, which has always been brilliant (see picture below). However, I have a question: why is there a single slit ...
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Superposition equation for a tilted diffraction grating

When we have a diffraction grating that is tilted at an angle, would the formula d sin θ = mλ still work?
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Why the center of circle is dark in this interference experiment?

As the image you can see, a lens with focus length of $f$ was cut into 2 parts, L1 and L2, a distance of $f$ between them. A monochromatic point source of light $S$ was put in the left of L1 with a ...
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Will tennis ball produce same interference pattern in double slit experiment if everything was scaled up?

Assume the same experimental setup as double slit experiment with electron but everything is exactly scaled up in size so that electron is replaced with tennis ball. Now we throw tennis balls at ...
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Minimum distance for two parallel beam to interfere effectively

Following is an illustration of two parallel monochromatic beams interfering in Bragg's law experiment. For these two rays to interfere, what is the minimum distance OF required? I understand that the ...
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Quantum description of radio antenna

I am trying to form a clearer picture of how a radio transmitter emits waves from a quantum point of view. The classical description is quite easy: the electrons oscillate in the antenna and, as ...
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Fabric of reality shadow photon partitioned off into parallel universes among themselves?

In fabric of reality interpretation of QM chapter 2 how does David Deutsch conclude that the "shadow photons" in the one-particle-at-a-time double slit experiments are themselves ...
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Would the central fringe in the Double Slit Experiment be less populated if we negatively charge the spot between the two slits?

Would the the interference pattern in the Double slit Experiment with electrons look different if we make the point between slits charged? Would the patterns elongate or would the distribution among ...
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Holograms as a superposition of many individual interference patterns

I've recently started reading about non-linear optics and holograms. While I do understand the basics of how holograms are made, by superposing the reference waveform on the object waveform over a ...
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Mach-Zender Interferometer with an external Phase shifter

On passing a input beam of form $\begin{pmatrix} { \alpha\\ \beta} \end{pmatrix}$ through a Mach-Zender interferometer with a phase-shifter of phase $\delta$ on either lower leg or upper leg of the ...
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Is it possible for two partially linearly polarized waves to interfere and produce a pattern?

I was wondering if it is possible to notice an interference pattern between 2 partially linearly polarized waves. If the polarization degree was good enough wouldn't we be able to notice some areas ...
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What if we replace the flat screen with a complete sphere? Double slit experiment with photons

I am trying to make this question a generic one. That's why it contains seemingly many questions. Light source --> slit-plate --> spherical screen Consider the classical double slit experiment ...
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Confused about diffraction/interference

I got confused when I was studying the interference patterns that arise in a film when light come from the slits. It is said that a require condition to the interference occurs using slits, is that $1&...
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Is it just a co-incidence that the interference pattern of light can both be explained using a classical wave and using a probability function?

Approach 1-Light can be thought of as a vector electric field wave. To explain the interference pattern, one can just add the electric fields like vectors and calculate the intensities. Approach 2- On ...
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Why do two-beam interferometers have a relatively broad "fringe width" compared to single-beam interferometers?

I recently overheard someone discussing the basics of interferometry setups. They said that two-beam interferometers have a relatively broad "fringe width" compared to single-beam ...
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Particle statistics and interference pattern

Does the particle statistics have some observational effect on interference (for ex. double slit experiment)? My doubt arises because of following reasoning: One particle at a time (Tonomura): ...
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Interference of em waves

If EM waves interfere, how is it that wave that is in my line of sight does not interfere with wave that is in someone else's line of sight which intersects my line of sight, and consequently make ...
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Why do we consider coherent waves interfere as if there is no distribution of energy as the wave progresses?

In my textbooks, youtube videos, different websites, I have seen that during calculations regarding interference of waves we derive the equations in such a way as if there is no distribution of energy ...
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Shouldn't a part of the ray have to travel $\frac{\lambda_2}{2}$ extra path in the medium $n_2$?

Basically, my teacher had given the class a question regarding thin film interference that, there is a medium with refractive index $n_1$ below that there is another medium with thickness $t$ with ...
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How to combine/calculate for interference using density matrices?

Let's assume following two density matrices are corresponding to the A and B in the Stern-Gerlach apparatus bellow: $\rho_A=\frac{1}{2}\begin{pmatrix}1&1\\1&1\end{pmatrix}$ $\rho_{B}=\frac{1}{...
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Question regarding Newton's rings

In the Newton's Ring Experiment why is the central fringe a light fringe? Why does constructive interference happen at the center? Does it have anything to do with the sense of thickness between point ...
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Why there is always a bright fringe at angle zero in light's double-slit experiment?

The explanation I read is that because at $\theta = 0$ the waves travel the same distance from both slits to A and thus have no phase difference. They add up constructively so there must be a bright ...
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Is it valid to use the small angle approximation in this problem?

I'm trying to solve this question. I use the equation $$\boxed{d\sin(θ)=mλ}$$ I keep finding $575$ $\mathrm{nm}$, the answer key says the result is $485$ $\mathrm{nm}$ but I think it's only possible ...
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Do we hear sound at pressure or displacement antinodes?

I have read from Young & Geller (2007), College Physics 8th Edition, Pearson Education Inc. (pg 385) that we hear sound at pressure anti-nodes rather than displacement anti-nodes as microphones ...
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Since neutrinos have mass, is there a neutrino aether that could be detected by a Michelson-Morley experiment?

If there are trillions of neutrinos per second passing through my body each second, would this density of particles qualify as a neutrino aether? If so, it seems in principle that an interference-...
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Interpretation Fourier Diffraction

I got familiar with interference and now want to understand it with the help of Fourier optics, as it is called. For the derivation of the diffraction integral the following setup is to consider: ...
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Stern Gerlach and interference

I recently came across this experiment: a beam of spin 1/2 particles pass through a Stern Gerlach apparatus oriented in the z direction. After passing through it and splitting, the beams are again ...
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Layer Interference: Reverse diffraction oder?

Brief in between question: Regarding the conditions for constructive interference on thin layers $m\,\lambda = 2\,d\,\sqrt{n-\sin^2(\alpha)}$, where $\alpha$ is the angel of incidence. For simplicity ...
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Fabry-Pérot-Interferometer: What Reflectivity

Apologizing for that narrow question, but considering such interferometer with mirrors characterized by Reflectivity $R$ and reflection coefficients $r = \sqrt{R}$, where $R$ describes the amount of ...
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Why do the Fringes in Michelson Interferometer move inward/outward?

We did this experiment using Michelson Interferometer of monochromatic source $\lambda$ to find the refractive index $n$ of dry air in a chamber of length $L$ by counting the number of fringes moved ...
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Where is the quantum interference term in a qubit state?

According to Wikipedia article on wave interference the probability of observing an object at location x in quantum mechanics for wave function $\Psi(x)=\Psi_1(x)+\Psi_2(x)$ is: $P(x)=|\Psi(x)|^2=|\...
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Add coherence length factor in source term for light source

I am trying to model the behavior of a Michelson-interferometer driven by a light source with a short coherence length (i.e. some centimeters at max.). By placing transmittive material in one of the ...
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Would there be a interfearence pattern if the phase difference is periodic function?

Consider the interference between the two waves $$\mathbf{E}_1=\mathbf{E}_{01}\cos(\mathbf{k}_1\cdot \mathbf{r}_1-\omega t)$$ $$\mathbf{E}_2=\mathbf{E}_{02}\cos(\mathbf{k}_2\cdot \mathbf{r}_2-\omega t-...

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