# 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.

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### Modifying the Michelson interferometer [closed]

If additional beams splitters were to be introduced to one of the beam paths in a Michelson interferometer leading to production of additional beams, each assigned a detector. Like this; Circles ...
1 vote
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### Confused about the principle Of Michelson Interferometer

Consider the figure that I found from an answer here: Michelson interferometer circular fringes Now the path difference in the image in clearly $$\Delta d= 2d cos\theta$$ and I know a phase ...
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### Interferometer designed to create diffraction in free space

I designed the following interferometer: If the light beam -theoretically- is very narrow , will light be diffracted away from point B from QED's perspective?
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### Mach-Zehnder interferometer and superposition

I've a doubt on interpretation of superposition in the interferometer Is it correct to say that in the Mach-Zehnder interferometer, the photon exists in a state of quantum superposition of the two ...
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### Understanding the math of the Michelson-Morley experiment

I'm having some conceptual misunderstandings of the Michelson-Morley experiment. The time for the beam going perpendicular ($t_{across}$) of the aether wind I am getting: (ct)^{2}=d^{2}+(vt)^{2}\\ (...
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### Double slit with off centre source, where does phase difference occur?

I am currently working through the following problem for my optics class. The setup as shown below is composed of a double slit sandwiched between two convergent lenses L1 and L2. A point source is ...
1 vote
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### Which method of laser diode operation is less likely to cause mode hopping: constant current or constant power?

If a laser diode is uncolled and operates in a CW mode then which method of operation is less likely to cause mode hopping: constant current or constant power?
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### Does QM recognise empty waves?

If a particle (photon) goes through a Mach-Zehnder interferometer it is accepted in quantum mechanics texts that in passes in both channels after first beam splitter BS1 and propagates there until BS2....
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### Why are the Michelson-Morley experimental results interpreted more broadly than the scope of the tested medium?

My understanding of the experimental design is that they tested for a stationary, luminiferous, light propagating, non-interacting with mass, uniform, ubiquitous medium. This is but one possible ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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?
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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. ...
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### 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 ...
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1 vote
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### 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 ...
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### 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
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### 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 $\lvert 1\hat{e}\rangle$ ...
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### 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 ...
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### 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 ...
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### 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, ...
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### Fringe pattern and ripples in the fringe visibility plot from interferograms

I am using a lens testing interferometer, where I record 4 to 5 interferograms with a 90$^{\circ}$ phase step between consecutive interferograms. In addition to the interferometer, I have also created ...
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### Single-Antenna-Single-Pass SAR interferometry

As I understand, for elevation mapping using InSAR, one typically requires an out-of-plane baseline to create the required phase difference between images to detect objects at height. This usually ...
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### How does partially constructive and partial destructive interference work in interferometers?

From what I have gathered, complete constructive or destructive interference results in all light or no light traveling a given path of an interferometer (correct me if this is incorrect). However, ...
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### What Is The Easiest Way to Measure a Short Distance With Laser Light?

I'm an EE, so please forgive if this question is dumb. The word "easiest" means, "What requires the least amount of optics experience?" "Short distances" means 0.01 to 1 ...