All Questions
Tagged with optics interferometry
161
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When building a fiber optic interferometer what methods are used to reduce microphonic effects?
When building a fiber optic interferometer what methods are used to reduce microphonic effects? I'm familiar with a few methods such as: enclosing the interferometer under a sound dampening cover, ...
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Are there any commercially made optical fibers which are made specifically to have very low microphonic properties for application in interferometry
Are there any commercially made optical fibers which are made specifically to have very low microphonic properties for applications in interferometry. While building a fiber optic interferometer I ...
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Why laser output power fluctuates after passing through two 1x2 fiber optic couplers?
When laser source is launched into two 1x2 50/50 fiber optic couplers connected as below the output power constantly fluctuates in range of 70 uW.
The fluctuation happen roughly one to two times per ...
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52
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Michelson interferometer but with 1 arm (Part 2)
I designed a setup similar to Michelson Interferometer but with one mirror only. So, there is an angle between the 2 rays to the detector:
In order to understand the result on screen, I used (Zemax/...
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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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57
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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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47
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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 ...
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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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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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53
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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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2
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134
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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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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 \...
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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 ...
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58
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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 ...
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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 ...
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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 ...
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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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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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2
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185
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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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399
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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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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 ...
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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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2
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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 ...
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Significance of the eigenvectors and eigenvalues of an interferometer?
An interferometer acting on $N$ modes can be described in terms of an $N \times N$ unitary transformation $U$ acting on the creation or annihilation operators of the modes.
I'm wondering if there is ...
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3
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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 ...
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2
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126
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How many fringes can pass by on a Michaelson interferometer?
A Michaelson interferometer is an instrument that most physics undergrads get to play with once or twice.
A beam splitter sends part of the light to each of two mirrors, the light returns, then hits ...
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479
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What is a 'good' coherence/correlation function for multimode spectra?
Following up on the question here and this answer in particular, I would like to pose the following question:
How to derive a formula for the coherence length of a multispectral source, such as a ...
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578
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Magically reappearing fringes in Michelson interferometer for large path length differences?
I've built a simple Michelson interferometer from two mirrors and a beam splitter according to the following schematic:
Image source
My setup differs from the one in the publication in that mirror M1 ...
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280
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Deriving the Interference Intensity of Michelson interferometer
I am trying to equate the equation i found wikipedia:
To the one given in my course notes which is:
Assuming a 50/50 beam split i have 1/2 where i should not have one:
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7
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Are human eyes interferometers?
It seems like 2 eyes is enough “wetware” to do interferometry inside brain. Can you definitely see some reason why this could not be happening, or some way to test if it does happen?
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317
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Where does energy go?
Where does energy go?
Given is the Michelson interferometer. One sends light in
in the form of a plane wave $E_0\exp[i(kx-wt)]$ into the interferometer.
The position of one of the mirrors is adjusted ...
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In a Mirau Interferometer what is the distance between the mirror and the beamsplitter?
A Mirau interferometer (shown left in the figure, next to the Michelson configuration to the right) is an important instrument for non-contact surface profilometry.
Briefly, taken from Wikipedia, &...
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Optical power between mirrors in resonant Fabry-Perot interferometer
I'm reading through the book Introduction To Laser Technology and just got to the section on Fabry-Perot interferometers. The book talks about the seemingly paradoxical behaviour of the optical power ...
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224
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Question about Michelson Interferometer
In Michelson Interferometer, the mirror that lies in the middle (half-silvered mirror), can reflect and let through light. But the light after being reflected by the half-silvered mirror, only let ...
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Can photons get captured in a Fabry-Perot cavity, and if so, what happens when it's detuned?
I'm imagining a three-step experiment with a Fabry-Perot cavity, and I'm not sure what would happen at each step.
First, suppose there is input light exactly resonant with the cavity. If I turn off ...
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Optics - interferometers and interference
I was watching a video of Sabine Hossenfelder, in which interferometers were a topic of discussion. Excuse me if the answer is obvious because I am not a physics pro by any means, just an interested ...
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158
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Reason why light beam hits detector
I was thinking about the basic structure of interferometers and I watched a video about it. I came across a simple illustration that looked something like this:
A laser beam is split into two ...
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180
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What does quadrature mean in the context of sine waves and resonance?
I heard a professor talk about quadrature in a sine wave representing resonance in time. What is the quadrature of the wave, and what does it mean for a quadrature to shift?
To be more specific, a ...
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0
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Orienting birefringent crystal the right way in an interferometer
I'm working in a lab that involves transforming the polarization state of one beam of light in an interferometer via a Barium Borate (BBO) birefringent crystal. As the polarization state is altered ...
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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 ...
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Why does constructive interference occur at zero path difference in a Michelson interferometer?
I was reading Introductory Fourier Transform Spectroscopy by Robert Bell.
In chapter 9 "Beamsplitters" he states for self-supporting dielectric beamsplitters:
"There are $\pi$ phase ...
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Michelson-Morley interferometer in free fall
We suppose that we have a Michelson-Morley interferometer in free fall, will there be no interference: the round trip time in both arms of the interferometer is the same?
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Small crack in bottom corner of a beam splitter
I'm working with a Sagnac interferometer. To split a laser beam (He-Ne), we are using a cubical, non-polarizing beam splitter from Thor Labs (BS031).
The beam splitter is fastened to a stand that is ...
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399
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Phase shifts in different beam splitter designs
I am trying to understand how a Mach-Zehnder interferometer works. It seems that it will work whether we use two beam splitters that consist of either
glass prisms glued together
a sheet of glass ...
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94
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Why is the sample interferogram given by the following integral of the intensity pattern?
I am trying to understand equation (2) in the paper by J. E. Greivenkamp with the title Generalized data reduction for heterodyne interferometry from year 1984. If you dont have acces to the article, ...
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Is $I(\lambda)=I(\tilde{\nu})$ true in general in Fourier Optics?
Say the spectrum of a light bulb is given by $$I(\lambda)=I_0exp\left(-\frac{(\lambda-\lambda_0)^2}{2(\delta \lambda)^2}\right)$$
(i.e. a gaussian)
if I want the intensity in terms of the wavenumber $\...
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Misconception with Fourier Transforms in a Gaussian Light source?
So for a Michaelson Interferometer , we know that the (complex) interferogram ($I=I(\Delta)$, $\Delta$=path difference between two mirrors) is related to the intensity profile of the light source $(...
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