Interferometry is the name for a class of measurement techniques based on the interference of coherent optical fields or other electromagnetic radiation. Generally, Interferometric measurements are extremely accurate, but can be difficult to perform. Common uses for interferometry are optical ...

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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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25 views

Could laser speckle patterns be used in diagnosing vision defects?

At the London Science Museum some years back, I saw a device which projected a laser speckle pattern and had a sign explaining that it would appear stationary for people whose eyes were correctly ...
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23 views

SU(3) interferometry with qutrits

It is well known that a two-mode interferometer can be described in terms of $SU(2)$ group Smerzi. I wonder if something symilar exists for three mode interferometer and qutrit states ? Not only ...
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37 views

Non resonant modes in cavity

I have a simple question. Suppose we have a laser with a cavity such that the frequency of the light that the laser emits does not match with any longitudinal modes allowed by the cavity. In ...
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22 views

Classical and semi-classical vs quantum interferometry

What is the difference between classical, semi-classical and quantum interferometry? How the detectors look like? As far as I know in classical interferometry light is treated as a wave, whereas in ...
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124 views

Michelson interferometry - is a compensator plate necessary?

I am studying the Michelson interferometer shown in figure 2 (similar design shown below) of the AMRITA vlabs tutorial. There it is stated that Since the reflecting surface of the beam splitter ...
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50 views

What prevents Digital interferometry in an optical telescope array?

I understand it is common to combine an array of radio telescopes in to a single instrument using interferometry. This has the photon collecting area of the combined radio telescopes but an aperture ...
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96 views

Coherence length requirement for interference

One property of light sources that is usually stated, which is of particular importance when trying to create interference fringes, is the coherence length (or coherence time). The equation for the ...
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227 views

Interferometers and Earth's motion relative to the Aether

Why was the Michelson and not the Fabry-Perot interferometer used to detect the motion of Earth relative to the Aether? Maybe the Fabry-Perot was used but we all know that the most famous experiment ...
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48 views

A problem regarding the Elitzur-Vaidman bomb tester

To quote wikipedia Step-by-step explanation After being emitted, the photon 'probability' wave will both pass through the first 50% reflecting mirror (take the lower-route) and be reflected ...
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85 views

Splitting a light wave

What I want to ask is what would happen if you split a single light ray (a photon) into two using a half silvered mirror? Would the emerging light rays have half the amplitude as the original one or ...
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69 views

Relativistic Doppler Effect and the Sagnac effect

What I think I know about the Sagnac effect can be found here. It occurs to me that the equations for calculating the time do not take the Doppler effect into account. I'm familiar with the very ...
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34 views

Optical interferometers resolution

I found this interesting list of optical interferometers: http://en.wikipedia.org/wiki/List_of_astronomical_interferometers_at_visible_and_infrared_wavelengths But I can't understand which is the ...
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How to shift a laser wavelength?

Recently I have read something about the laser surface velocimeter, and after I have to rebuild from scratch (university project), I got a question: In the description they wrote that one of the laser ...
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163 views

Interferometer problem about periodic fringe patterns [closed]

Please,kindly help me; my teacher assigned me problem set, and she never went over anything about interferometers in class. Also, there is almost no information about about how to solve interferometer ...
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2answers
102 views

Polarizing beam splitters for X-rays?

What is the lower bound for the wavelength concerning polarizing beam splitters? Especially I ask for interferometer experiments with single photons. Of course I know that they exist for all ...
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155 views

Is that a result of thin-film interference?

Several years ago, I was laying on my bed and had a CD shaped transparent plastic disk (which was covering a 100 CD stack), basically a transparent CD. I don't know why but I took my phone and took a ...
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54 views

Bandpass of diffraction grating - exit slit width?

I'm supposed to derive a relation for the range of wavelengths that's being transmitted by a spectrometer (bandpass) in terms of the dispersion, focal length and exit slit width. Given grating is ...
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122 views

Fabry Perot Etalon - changing wavelength and plate distance

Given reflectivity $R = 0.75$, an etalon is used as an interference filter, transmitting light of wavelength $4.3\mu m$ at normal incidence. The full width half maximum is about $\Delta \lambda = 0.2 ...
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2answers
506 views

Calculating the coherence length from a spectrum

I have measured the spectrum of the LED in my interferometry set-up, and now I want to calculate the coherence length from it. A commonly found formula is $l_{coh} = \frac{c}{\Delta f}$, sometimes ...
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53 views

Rotation speed measurment

Could anyone please explain with simply how we can measure the rotation speed of an object using the Sagnac Interferometer ?
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42 views

Alma correlator for visible light and for space based telescopes?

I was shocked to see that one can simulate interferometry on a computer like the ALMA Correlator described by this video (posted on Wikipedia's article on ALMA) Is is possible to do the same in ...
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44 views

What type of interferometry set up do I need to image a small structure at a distance?

Please forgive me, optics isn't my forte. I'm trying to work out how to image the surface structure of an object at a distance. Considerations are: Monochromatic light- it must be imaged in the ...
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1answer
90 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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102 views

Pattern in the Michelson Interferometer

I have a question about the Michelson Interferometer with spherical waves: I know that the pattern produced by this kind of waves is a pattern of concentric circles. But what I'm not sure is how the ...
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72 views

Can alimentary packaging film be used to make a Fabry-Perot interferometer?

An alimentary packaging film consists on a thin plastic layer. If we put two of this films one on the other, could this acts as a Fabry-Perot interferometer? (I don't have the appropriate material at ...
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116 views

Finesse of an Fabry-Pérot interferometer

during an undergrad experiment we have to estimate the finesse of an Fabry-Pérot interferometer. The reflectance $R$ is given so the theoretical value can be calculated by $\mathcal{F} = ...
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325 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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89 views

Source of beating phenomena of a Michelson interferometer?

I was discussing the reason why we see beating from a Michelson interferometer, and one of my friend said it 's because the light have different frequencies, therefore, they would be out of phase. ...
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95 views

Michelson interferogram white light pattern symmetry

Why is the white light of the interferogram produced by using Michelson Interferometer necessarily symmetric? This is really hard to think.
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37 views

why using a EM spectrum produces a narrower fringes

I'm trying to figure out a physical reason of why a broader pulse turns out to give a narrower fringe, although I know mathematically the fringe is just the fourier transform of the pulse on the ...
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1answer
188 views

Why removing one slab in Michelson-Morley experiment causes an elliptical fringe pattern?

I performed Morley experiment using He-Ne laser. Two glass slabs were there and circular fringes were formed but when I removed one slab elliptical fringes were there (and less intense fringes). Why? ...
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264 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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163 views

Educational applications of a small Michelson interferometer?

The community college where I teach has some nice old Michelson interferometers. There appear to be a bunch of versions of these that used to be sold (may still be sold?) which were all probably ...
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505 views

Beam splitters and Mach-Zender interferometers

I have a question (my very first here) related to 50/50 beam splitters as used in the Mach-Zehnder interferometers (see for example the Wikipedia page). Let's concentrate on the input beam splitter: ...
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SHS Interferometer and diffraction limit

I'm currently researching Spatial Heterodyned Spectrometers (SHS) and I'm a bit at a loss understanding the influence of the diffraction limit. I'll be measuring a diffuse visible light source with ...
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829 views

How is a one position shift of an interferometer fringe pattern defined?

When Michelson and Morley conducted their 1887 interferometer experiment, they were expecting a fringe pattern shift of 0.4 (see the chart at http://en.wikipedia.org/wiki/Michelson-Morley_experiment). ...
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274 views

Michelson–Morley @ Home

The Michelson-Morley experiment seems to have taken many years, resources and a nervous breakdown to complete. Is it possible to recreate a variation of this experiment at home for say, under $1000, ...
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506 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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121 views

Understanding a sagnac interferometer with the half-silvered mirror reversed

I've been trying to make a simple puzzle game based on quantum optical circuits. Problem is, I don't actually know the physics that well (this is a hobby project with the goal of increasing that ...
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1answer
363 views

How does a warp field interferometer work?

Assume I have a solid grasp of undergraduate physics. From what I've read the warp field interferometer is supposed to be a sort of Michelson interferometer, except instead of adjusting the ...
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298 views

Misaligned Mirror on Michelson Inferometer

If one of the outer mirrors on a Michelson interferometer was to be misaligned by a small angle of theta, what would be the shape of the interference pattern in the detector plane? What would happen ...
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336 views

Why does heterodyne laser Doppler vibrometry require a modulating frequency shift?

On the wikipedia article (and other texts such as Optical Inspections of Microsystems) for laser Doppler vibrometry, it states that a modulating frequency must be added such that the detector can ...
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173 views

Image contrast as function of exposure for a CCD detector

In a laser interferometry experiment, we project a pattern of interference fringes onto a CCD sensor. For best results, we want good contrast between the bright and dark fringes, and we carefully ...
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66 views

Does a FTS work on the same principle as a michelson (amplitude division) interferometer?

As far as I can tell within an Fourier Transform Spectrometer the spectral information is gained from changing the path length along one arm, this sounds very similar to a michelson interferometer but ...
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576 views

How is the Hanbury-Brown and Twiss effect used to measure the size of stars?

I understand what an Hanbury Brown and Twiss (HBT) interferometer does, but how can this be used to measure the apparent angular diameter of some object? What is the mathematical explaination?
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396 views

how does phase-shifting principle in interferometry work?

I have been using the coherence scanning interferometry (or also known as white light scanner), where it collects images containing the fringes. The system is able to produce the depth profile for one ...
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3answers
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Can the Hanbury-Brown and Twiss effect be used to measure the size of composite objects like galaxies?

I know that the Hanbury-Brown and Twiss effect can be used to measure the size of stars. Can it also be used to measure the size of galaxies?
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184 views

Simplest interferometer

I want to build simplest interferometer which should be able to measure movements down to fraction of wavelength. What is the simplest scheme for that, and what are the requirements for a laser? I ...
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Could many widely separated space telescopes be combined for VLBI on IR/visible wavelengths?

I have read about ground-based Very Long Baseline Interferometry telescope arrays able to achieve huge resolution at IR/visible wavelengths. There are also space-ground VLBI configurations in ...