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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If I know in advance I'm getting an interference pattern, wouldn't I have time to remove the splitter so the which-path information would be know?

Check the image below, from this excellent explanation of the quantum delayed eraser. My question, and please forgive me if it is a naive one, is that first the photon reaches detector A, which tells ...
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Can two waves interfere head on?

Can two waves (like sound or electromagnetic waves) interfere head on? If yes, and suppose they are out of phase with each other and thus interfere destructively, where does the energy of the waves go?...
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Can there be interference between a proton and an electron?

For example, we know that we can interfere two different electrons or two different protons by employing them in a double-slit experiment. Now suppose, we mix protons and electrons and shoot them ...
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Will two coherent sources of orthogonal polarization angle form the known interference pattern or there will be difference?

if i have a laser beam then i split it into two beams with ratio 1 : 1 then i take one of them to change its polarization angle (90) degree by passing it through an optically active substance then we ...
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Thin film Interference pattern

Why exactly for this minima condition is: path difference = $(2n-1)\lambda/2,$ instead of $(2n+1)\lambda/2$? And what is the starting order of minimal here? Also, what does a negative path difference ...
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What do fringe patterns have to do with VLBI?

I think I have fundamental confusions with how VLBI works. I don't know why: Resolution increases when incident rays meeting to a focal point from a farther separation along an axis perpendicular to ...
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Maintaining phase relationships and other general principles of interferometry

I have a few confusions with some basic principles of interferometry. Bob Campbell's So you want to do VLBI writes: Phase relationships among all points on the wavefront will be preserved ...
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Difference between 'white light' and spectral light for rings of Newton

In my book of waves and optics, there's a chapter about the rings of Newton and as a question there is: how is the interference pattern when we use white light, considering me it's : there are rings ...
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Michelson interferometr electromagnetic wave formula [duplicate]

I don't understand why we use this formula: Instead of this formula: I mean, why we ignore $\omega\cdot t$ part.
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Why do we need cross-polarised light for observing conoscopic interference patterns?

I've performed some experiments for projecting conoscopic interference patterns. In some set-ups are used two circular polarizers one before and one after the birefringent crystal. I can imagine that ...
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Formulae for destructive interference [closed]

There are two formulae for destructive interference. In which situation do we use them? $$(n+1/2)\lambda $$ and $$(n-1/2)\lambda $$ I'm confused as my book has mentioned the first one but In ...
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How did scientist get photos of wave function of electron in the double slit experiment? [closed]

In the double slit experiment I know that the electron fires as a particle one at a time then splits goes through both slits and recombined and interferes with itself and hit the wall creating a ...
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Least-square fitting to data (sine function): what is the error of the derived fit parameters?

I have a set of data. I want to fit it to a sine function of the form : \begin{equation} f(x)=A sin(\omega x+B)+C \end{equation} I use the least-square method to find the appropriate fit-parameters ...
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Photon bunching and polarizers

I'm trying to understand how polarizers affect bunched photons. Or, more generally, how a projection operator affects a two-photon state corresponding to photon bunching. Toy example: Imagine you ...
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Diffraction pattern vs Interference pattern

I am not confused with difference between Young's double slit experiment and diffraction. In Young's double slit experiment, the interference pattern is bright fringes separated evenly with ...
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Single photon interference, state “top” current theory [duplicate]

Is there a simple generally accepted explanation for single photon interference? Does each photon interact with or see both slits?
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Wavelength and Lattice constant - need to be the similar magnitudes to have interference?

I was taught that they need to have similar magnitudes but I did an exercise last week and the magnitudes were different by 3 decimal places. Before I also noticed them being either the same or maybe ...
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Macroscopic objects - Interference

In Mcintyre's QM book he writes: What does he mean by "a macroscopic object strongly interacts with the environment" for there to be no interference? Why/how does the wave function of macroscopic ...
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Why does light show a no interference result?

I was reading the first chapter in the Feynman lectures volume 3 about quantum mechanics and I understand the concept that 'interference' means $P_{12}=P_1+P_2$ as expected, however when the electron ...
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Bubble optics, impact

My 8 years old daughter was blowing soap bubbles. Most of the bubbles had color. She randomly choses a bubble with colors and lands it on the wand. Instantly it's color is gone. If she blows this ...
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“Partial” Total Internal Reflection

Can partial TIR happen? Consider the image present in this link Here, at point D, TIR happens, but also there is transmission. Is "total" internal reflection a misnomer?
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Confusion regarding path difference by glass slab in YDSE

If in a YDSE experiment the setup is immersed in a medium $n_{med}$, and a glass slab of thickness t of another medium $n_{glass}$ is introduced in front of one slit, then is the path difference due ...
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How can a double slit interference pattern be created without out going through a double slit

When I create a double slit in a mirror by removing the paint and silver I get a beautiful interference pattern. What’s interesting to me is that I get one in the opposite direction too. What has me ...
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Fringes of equal inclination (Haidinger fringes) Why is the interference pattern circular?

From Hecht optics 5th edition: It says 'With an extended source, the symmetry of the setup requires that the interference pattern consists of a series of concentric circular bands centered on the ...
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What kind of light coherence is required for an image

If 1- Optically speaking, an image point (or pixel) is a light interference pattern 2- interference patterns require phase coherence then 3- the source of the image point must emit coherent light ...
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Physics Young's Double Slit Problem

In a Young's Double Slit experiment, the separation of four bright fringes is $2.5\ mm$, the wavelength of light used is $6.2 \cdot 10^{-7}\ m$. If the distance from the slits to the screen is $80\ cm$...
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Possible to change optical properties of tissue?

I am looking at an optical coherence tomography scheme which is based on a michelson interferometer. The basic idea is that a laser beam is split by a beamsplitter, half of which goes into some tissue ...
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Time-of-flight vs. which-path information for single photon interference

I wonder how different path length and therefore different times required for each path lead to interference. Wouldn't it be in principle be possible to tell which path was taken by looking carefully ...
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Why oil films still have color when illuminated by an incoherent source (sun) at oblique incidence

I understand how coherent light can produce interference patterns with a thin oil film. However the sun is a spatially incoherent light source. How can it be that at oblique incidence I still see ...
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How can I focus a laser in the gap between two slits?

I’m trying to focus a green laser in between two slits. The slit width is 0.2mm and gap between the slits is also 0.2mm. I measured the laser’s minimum spot size. It’s elliptical with major and minor ...
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Young's Double Slit, phase difference and path difference

To produce an interference pattern, the light sources must be coherent right? Coherent by definition means constant phase difference between waves of the same frequency so that means waves can be ...
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Why is a point source required for observing perfect double slit interference?

What would happen with a non-point but coherent source (some kind of ideal flashlight which produces perfectly coherent light for example)?
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To calculate the transmission through a thin film interference structure in multi-layer coating to infinite reflections need to be taken into account?

For a two layer structure shown below I was thinking about the transmission and reflection of light at each interface. As I consider this more and more it seems like there is an infinite number of ...
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Why waves in superposition pass through each other without interference in same medium?

Wave can interact constructively (add up) or destructively (cancel) but how about when they are in a superposition state why is there no interference when they meet up in same medium? Imagine 2 pulses ...
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Why do the two slits of a double slit experiment not make light coherent and create an interference pattern if monochromatic light is passed through? [duplicate]

If a narrow slit makes monochromatic light coherent, why is light required to pass through the single slit before the double slits in Young's experiment? Wouldn't the double slits individually make ...
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Destructive interference of light and destroying energy?

I've had a hard time with destructive interference of light, and the possibility of destroying energy. I've read countless articles here and elsewhere, leaving me with the answer of something to the ...
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Double slit diffraction

In the intensity pattern of double slit there are two terms one for single slit diffraction $\sin^2a/a^2$ and another is double slit interference $\cos^2b$.In the intensity pattern of double slit ...
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Proof of interference fringes take the same shape as the shape of the film? [closed]

(First of all I should mention time talking about interference between two reflecting rays thinking e.g. Newton's rings.) Studying wave optics I have found that at the fringes take the same shape as ...
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Why gravitational wave stretches on $x$-axis would necessarily compress on the $y$-axis?

I read gravitational wave is a traverse wave, usually produced by inspiraling neutron stars or black holes, and laser interferometer such as LIGO is commonly used to detect them, since the setup of ...
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What is the reason behind diffraction of light?

What is the actual reason behind diffraction of light? I want to know how is the phenomenon diffraction explained theoretically in physics (best if the discussion limits itself to classical physics). ...
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Dimensions of Faraday shielding mesh

Why should the spacings of the wires that constitute a Faraday cage be smaller than the wavelength of the radiation we wish to prevent from penenetrating inside the cage?
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Unable to get interference from milk using Time domain OCT (Michelson Morley interferometer) approach

I was able to construct time domain Optical coherence tomography based on Michelson Morley interferometer using a LED. While testing the interferometer, I used glass slide, layers of scotch tape. I ...
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Interference using composite lens

I encountered a question while attempting an exam. I cannot really understand how to go about it. It is clear that the concave part forms the image at a distance $3 \lambda /2$ behind the lens, and ...
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Are photons blinking? [closed]

Is a photon passing through a point in space blinking relative to that point? If the photon for some reason destructively interfere with it self at that point, what happen to it? is it off or ...
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Newton's rings. Interference by division of amplitude

We all know that in wedge shaped film fringes are equally spaced.Being a wedge shaped film Why does the fringe width decrease as order increase in Newton`s ring ?
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What does the interferogram in Michelson interferometer mean about the topology of the specimen?

I'm want to know how can I evaluate the surface of a fibre by using the interferometer of Michelson. The object beam in this method is reflected from the object and combined with the reference beam to ...
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A confusion regarding the single slit interference

So I came across the single slit interference in which a parallel beam of light is passed through narrow slit as shown in figure below. (I made only 3 rays in figure for simplicity there are actually ...
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Theoretically, if I swish a laser back and forth fast enough/at the right frequency on a distant surface, will I get an interference pattern?

Just curious. I’m kinda stumped and am interested in how one would go about visualizing/calculating this.
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Anti-reflection thin films

When you put an anti-reflective thin film on a lens of sunglasses for example, how do they account for all of the wavelengths within the visible spectrum? In order to counter reflection, you would ...
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Can this be considered the Newton's rings?

It can be made by pointing a laser pointer directly to a mirror at low angle and observing the reflection behind the laser pointer. No convex or concave lens needed unlike the Newton's ring experiment ...

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