Tagged Questions

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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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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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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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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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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57 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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64 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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95 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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30 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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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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148 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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46 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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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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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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85 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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54 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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59 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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80 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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216 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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82 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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73 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
167 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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187 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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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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430 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 http://en.wikipedia.org/wiki/Mach-Zehnder_interferometer). Let's ...
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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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550 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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234 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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423 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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102 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
305 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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2answers
232 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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276 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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155 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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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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473 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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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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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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174 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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71 views

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 ...
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277 views

A moderate introduction to Hanbury Brown Twiss interferometry in particle physics

For astronomy, as originally invented, the Hanbury Brown Twiss interferometer is good for finding the angular diameter of stars and is not a rapidly fluctuating observable like the amplitude in ...
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580 views

Is it possible to make a hydrogen-alpha solar scope?

Is the construction of an etalon / Fabry-Pérot interferometer within the reach of amateur telescope makers? Are there any resources pointing to such projects?
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How do animal perceive distances with their eyes and ears

I am studying how animals (including the human beings) can perceive distances thanks to their eyes and their ears. I am focusing on the fact that they always go in pairs: two eyes, two ears, etc. ...
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197 views

Are Newton's gravity waves detectable by a laser interferometer?

Newton's theory of gravity supports "gravity waves" in that moving objects cause changing gravitational fields. For example, two bodies rotating around their center of mass will have a stronger ...
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554 views

In interferometry, what is the origin of the name “Airy function”?

In interferometry (specifically, in the domain of Fabry-Perot cavities), the function $$f(\phi) = \frac{1}{1 + F \sin^2 \phi}$$ , which describes the shape of the resonant structure of the cavity, is ...