Questions tagged [interferometry]

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 component metrology and stellar interferometry, although there are many applications.

Filter by
Sorted by
Tagged with
1 vote
1 answer
8 views

Why fiber optic Sagnac interferometers don't produce multiple interference fringes

I have seen a few Sagnac fiber optic interferometers however, those that I've seen don't produce multiple fringes but rather just one luminant dot with varying intensity. Even if a beam expander is ...
0 votes
1 answer
46 views

How to align a Mach-Zehnder at 810 nm?

I have a task to arrange MZI using very weak source with photons coming one at a time. On top the wavelength is 810 nm. How to 'see' the interference pattern to 100% in one channel and 0% in other. I ...
0 votes
1 answer
41 views

What are the disadvantages of using a single mode Fabry-Perot laser diodes in interferometry, as opposed to distributed feedback laser diodes?

What are the disadvantages of using a single mode Fabry-Perot laser diodes in interferometry, as opposed to distributed feedback laser diodes? I'm specifically interested in potential problems that FB ...
2 votes
1 answer
295 views

Can we tune the Mach-Zehnder modulator or equally mix it with a pure RGB laser signal with a broadband optical source at the same efficiency?

I would like to find out if a dual-parallel Mach-Zehnder modulator with either 1) fixed optical path lengths or 2) variable optical path lengths commensurate with today's announcement by a team of ...
0 votes
1 answer
36 views

Mach Zehnder Do-it-yourself

I have a red laser and BS. Can I make MZI at the lab? I heard that is very difficult to achieve the calibration. What is expected to be seen after BS2? A dark spot at centre with fringes around? I ...
1 vote
3 answers
538 views

Measuring coherence length with the Michelson Interferometer

In lab, I've been asked to measure the coherence length of a green-light laser source using a Michelson Interferometer. To do so, I configure the interferometer such that a circular fringe pattern ...
0 votes
1 answer
43 views

Is the interference stable?

In a Mach Zehnder interferometer if we use one at a time photons and tune it so the first several to arrive in channel D1 after BS2 will all next arrive also in D1? Are there reasons that some will ...
0 votes
1 answer
214 views

What is the unbalanced Mach-Zehnder interferometer?

I read about unbalanced Mach-Zehnder interferometers in investigating the time-energy entanglement. I wanted to know what is it. and what is its purpose? Thank you.
0 votes
2 answers
81 views

Phase difference in Michelson Interferometer

I'm currently taking a quantum mechanics course in university and our professor introduced us to the Michelson Interferometer (or at least what I believe is an apparatus based on it), where a light ...
1 vote
1 answer
288 views

Phase unwrapping in interferometry

I observed that in "interferometry" is used a process called phase unwrapped. This process can be done by using complicated algorithms but I was not able to found an example more simplistic. If somone ...
0 votes
1 answer
26 views

Mode Interferometers (MMI) versus waveguide couplers

In Photonics Integrated Circuits Mach-Zender (MZ) modulators are very often used. This design splits one wageguide into two spatially separated waveguides and makes them to rejoin, in order to ...
1 vote
1 answer
191 views

Time difference evaluation in a Michelson-Morley apparatus with arbitrary orientation

Historically, by assuming the validity of the Lorentz-Fitzgerald contraction, the null result obtained in the Michelson-Morley experiment can be explained. In particular light travels along the two ...
0 votes
0 answers
21 views

How HBT interferometery works?

I am still confused about how HBT interferometry for star angular size works after reading about it on the internet and in papers. Mathematics usually does not help before I do not catch the way the ...
2 votes
1 answer
66 views

What are the similarities between a beam splitter and a double-slit?

More generally, my question is about the similarity between an $N$-slit and an $N$-mode beam splitter. Conceptually speaking, would it be accurate to say that the beam splitter is just the discretized ...
0 votes
1 answer
66 views

Can LISA observe BH beyond the observable universe?

Reading the paper "Astro2020 Science White Paper Where are the Intermediate Mass Black Holes?", and the plot in Fig.1, page 5, it seems LISA can see IMBH beyond 100 Gpc...Since the ...
4 votes
3 answers
2k views

I polarize the slits (one H, the other V) of a Young's double-slit. If my source is H or V, do I see fringes? What about if my source is D or AD?

In my journey to understand light better, I build a "polarized Young's interferometer". Imagine the following polarizations: horizontal, vertical, diagonal, and anti-diagonal (H, V, D, and ...
1 vote
1 answer
56 views

How close to reality is my handwaving argument about Fabry Perot interferometers?

Under this answer to https://astronomy.stackexchange.com/q/55437/7982 I wrote a comment where propose the uncertainty inequality roughly written1 as $\Delta E \Delta t \ge h$ or for photons $\Delta \...
0 votes
1 answer
89 views

Which experimental setup replicating Michelson-Morley experiment had the longest path of light?

After the Michelson-Morley (MM) experiment many scientists performed similar experiments using the original MM experimental setup, or different derivative experimental setups employing lasers and ...
0 votes
0 answers
39 views

Is it possible to create Fabry-Pérot Interferometer with one partially transparrent and one non-transparent mirror?

In the literature sources I've found so far about Fabry-Pérot interferometer there are only example schematics of the interferometers in transmission - light source is placed from one side of the ...
0 votes
1 answer
38 views

Michelson interferometer moving mirror by half wavelength

With expanding beam I understand I will get circular fringes, and I understand if you move the mirror by d the path difference change of the interfering beam is $2dcos\theta$. But I don't understand ...
0 votes
0 answers
59 views

Single-photon interferometry with fibers: the very first experiment

I am looking for the very first published experiment in a relevant journal with all the following features: Michelson or Mach-Zender light interferometry is demonstrated The arms of the ...
0 votes
0 answers
37 views

Getting the power spectrum from an interferogram

I'm doing analysis for a laboratory task where we used a stepper motor to vary the position of a mirror (in a Michelson interferometer) to get interferograms using different light sources. I have been ...
1 vote
1 answer
1k views

Calculating Coherence Length and spectral width given an interferogram

I'm currently doing a lab in which we use a Michelson-Morley interferometer to analyse different light source. One of the mirrors in the interferometer is moved by a stepper motor. One of the light ...
0 votes
0 answers
56 views

Question on Feynman's Improved Stern-Gerlach Experiment rotated about the $z$-axis

I'm having trouble understand Feynman's reasoning that particles in Fig. 6-5 (b) will end in an unknown state. Feynman reasons quote: Suppose that we put an apparatus in front of S which produces a ...
0 votes
0 answers
25 views

Atom Interferometer Contrast

I have made a simulation of a Raman beam based atom interferometer in a Mach-Zehnder configuration. In this way, the electronic state of the atom changes as well as the momentum when diffraction by ...
0 votes
0 answers
18 views

What is the allowed wavelength range over which the Fabry Perot intensity pattern is formed?

I'm working with a Fabry Perot cavity with a length of 55 mm and an incident wavelength of 1550 nm. From theory the FSR of the FP cavity can be either computed using the equation FSR = λ^2 / (2 n L) ...
1 vote
0 answers
28 views

What are the causes for $g2$ ( intensity) value changes in a Mach-Zehnder setup at a fixed reference path and fixed sample?

I'm using a Multimode laser passing it through a Mach-Zehnder interferometer. I am able to get almost constant $g2$ (intensity) from the sample. However, the reference arm intensity keeps fluctuating ...
0 votes
1 answer
97 views

How exactly does Ligo achieve complete destructive interference with just an interferometer?

Ligo works by destructively interfering light from a laser using an interferometer. Its said that no light enters the photo detector when all mirrors are the same distance. However,based on my ...
0 votes
0 answers
47 views

Decomposing circular diffraction patterns

I have the following diffraction pattern produced by a fabry-perot etalon The red represents the center of that pattern. Taking the mean intensity of the pattern as a function of the radius from the ...
0 votes
0 answers
25 views

Pattern of source-tracking two-element radio interferometer

In a two-element adding Interferometer, the phase difference comes about as EM-waves from a source at an angle $\theta$ to the baseline-normal generally cover different path lengths when travelling to ...
0 votes
1 answer
40 views

Michelson interferometer: beam splitter affects amplituedes?

Let's suppose an initial plane wave $\vec{E}=\vec{E_0}e^{i(\vec{k}\cdot\vec{r}-\omega t)}$ enters a Michelson interferometer . Let $\vec{E_1}=\vec{E_{01}}e^{i(kz-\omega t)}$ and $\vec{E_2}=\vec{E_{02}}...
5 votes
1 answer
655 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 practice ...
0 votes
0 answers
12 views

Lowest numerical aperture SIM microscopy

What is the lowest numerical aperture objective that can support SIM microscopy? Also, how does the NA affect the spatial frequency or contrast of the resultant standing wave?
1 vote
0 answers
35 views

How is a delocalised state realised and what is its wavefunction?

Gravitationally induced entanglement experiments aim at studying the quantum nature of gravity trough the interaction of a delocalised particle state with another system. The various papers on the ...
0 votes
1 answer
31 views

Fabry-Perot interference pattern at non-normal incidence

I'm confused about exactly how the interference happens. The original beam (at the bottom) comes in at an angle, and multiple reflected rays come out of the second mirror. But those rays are spatially ...
0 votes
0 answers
25 views

How does the change in cavity length effect the interferometric frequency of a Fabry Perot cavity?

I'm working with FBG-based Fabry Perot interferometers, considering three FBGs in series to create 2 FP cavities. I'm confused about the following two things and cannot seem to get clear answers from ...
1 vote
2 answers
88 views

Understanding Entanglement basis change in a practical sense

I am trying to understand the concept of basis change for a pair of entangled particles (in mathematical sense as well as what it means in case of detection on detectors in a Mach-Zehender ...
0 votes
2 answers
154 views

Difference between LIGO and Michelson-Morley interferometer

The LIGO interferometer looks like a huge Michelson-Morley experiment showing interferences and the gravitational waves are described as waves propagating on the 'spacetime fabric'. LIGO detects ...
0 votes
3 answers
293 views

How can I simulate michelson's interferometer circular fringes?

I wanto to simulate the circular fringes on a screen for the michelson interferometer. I know how to identify if there will be a destructive or constructive interference, but what about the radius of ...
0 votes
1 answer
283 views

Phase Shifting Beam Splitter

I am trying to make sense of all these answers in: Phase added on reflection at a beam splitter? and web search results. So my understanding is that the actual phase shift depends on the beam splitter ...
2 votes
1 answer
476 views

Elitzur-Vaidman Bomb Detector

The Elitzur-Vaidman bomb detector is a theoretical device that can detect whether photon-activated bombs are functional without detonating all of the test bombs by using quantum mechanics principles. ...
15 votes
5 answers
8k views

Phase added on reflection at a beam splitter?

If we have light of a particular phase that is incident on a beam splitter, I assume the transmitted beam undergoes no phase change. But I thought that the reflected beam would undergo a phase change ...
1 vote
2 answers
228 views

Interference in split and recombined beam

let us consider the following setup of beam splitters: single photons enter beam splitter A with R/T ratio of 50:50 and split into two paths A1 and A2. A1 undergoes a phase shift of X and then using ...
0 votes
0 answers
84 views

Calculating probabilities for beam splitter setup

let us consider the following setup of beam splitters: single photons enter beam splitter A with R/T ratio of 50:50 and split into two paths A1 and A2. A1 enters beam splitter B and A2 enters beam ...
2 votes
0 answers
20 views

How to model the effects of diffraction for a convex lens?

I am using a convex lens in a wavefront-measuring interferometer for testing microscope objectives, where the lens images the exit-pupil of the objective onto my camera. It is my understanding that ...
1 vote
0 answers
25 views

Griffiths Consistent histories MQS state in Mach-Zehnder experiment

In Robert B. Griffiths' Consistent Quantum Theory, he describes a variant of the Mach-Zehnder interferometer experiment where a detector represented by "off" state $\lvert 1\hat{e}\rangle$ ...
-1 votes
1 answer
30 views

Aqueous Equivalent of the Michelson-Morley Experiment [closed]

This question relates to the Michelson-Morley experiment and whether anyone has so far proposed an equivalent experiment using aqueous waves instead of optical waves. If it is true that (i) The ...
0 votes
0 answers
14 views

How to Filter-out Mid Spatial Frequencies?

In my Twyman-Green interferometer, I am testing a microscope obejective. The reference spherical mirror introduces Mid Spatial Frequencies (MSFs), whose effect on the wavefront measurements I'm ...
0 votes
1 answer
65 views

The purpose of acoustic optical modulator (AOM) in Heterodyne Interferometry for Plasmas

I do not understand the purpose of an acoustic optical modulator (AOM) in a heterodyne interferometry system. Take the system below as an example (taken from a UW Dissertation) My understanding for a ...
0 votes
0 answers
18 views

Explain laser stability and interferograms relationship

I am using a Twyman-Green interferometer to record phase-stepped interferograms. The interferometer uses a monochromatic diode laser (visible light). As you observe the interferogram on the screen, ...

1
2 3 4 5
8