Optics is the study of light, and its interaction with matter. It includes topics such as imaging systems, fiber optics, lasers, quantum optics, and more.

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The angle of incidence of prism if emergent angle is 90°. Answer in terms of angle of prism and refractive index of prism [on hold]

A ray of light is incident at an angle of incidence i on one face of a prism of angle A (assumed to be small) and emerges normally from the opposite face. If the refractive index of the prism is n, ...
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For a light of given frequency, what does the amount of refraction in a variable medium depends upon?

I want to know whether the amount of refraction of a given monochromatic light depends solely upon the density of the of the medium ( increase the density to increase the angle of refraction), or ...
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43 views

Does Fermat's principle of least time apply to sound waves?

I am reading Feynman's presentation of Fermat's Principle of Least Time, which explains the behavior of light; does it apply to waves in general? for example sound waves or waves on the surface of ...
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41 views

Determining the path of a light ray

Let's consider a ray in the plane $xy$. Let the refractive index be defined in any point of the plane with the function $n(x,y)$. In time $t=0$ the ray is located in coordinates $(x_0, y_0)$ and its ...
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426 views

why cant we use a pair of polarizer ( whose pass axis are oriented at 90 degrees ) to protect from entry of harmful radiation?

If a pair of polarizers can block EM waves passing through it, then can we use them for protecting against harmful radiation (in nuclear reactors and also in spaceships) in thermo flasks to ...
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473 nm light through a single mode fiber designed to operate between 1500 and 1600 nm

Can we send light with 473 nm through a single mode fiber designed to operate between 1500 to 1600 nm spectrum? The radius of the fiber core is 4.25 micrometer, NA=0.12 and the single-mode cut-off is ...
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27 views

How is angle measured by telescope in spectrometer is twice the prism angle [on hold]

While measuring the angle of the prism with the help of telescope in a spectrometer (see figure below), the observed angle is twice the angle of the prism. Can someone prove it geometrically? Edit : ...
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Is my window's semi-transparency a consequence of elementary quantum mechanics? [duplicate]

Studying mathematical concepts of quantum mechanics, I have recently become familiar with the classical model of one-dimensional particle being scattered by a potential barrier. As a mathematician, I ...
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32 views

Why does radiance remain constant along rays of light through empty space?

In Radiometry, radiance (L) is defined as flux density per unit area per unit solid angle. If we move further along a ray, away from a point, shouldn't the radiance decrease? I am unable to grasp an ...
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Is there any review paper on spatial light modulator?

I need a review paper on the various types, principles and characterization of spatial light modulator. But it seems I could not find one. Any one has a good idea?
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15 views

Lens to optimize field of view through a tube

I have a tube of length L and radius R with L>>R. I want to place a lens in the tube such that I have the biggest field of view when I look through the tube. Is the correct answer just the obvious ...
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51 views

Why the image is being formed at the surface?

Last week I encountered a very cool optical phenomenon. A photo was sandwiched between the two glass plate to make the paperweight. The cool part is the picture seems to have been pasted on the top ...
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52 views

How I can launch light into PM fiber

A polarization maintaining fiber preserves the linear polarization of the light at the output, the light at the input must be linear polarized to see signal at the photodetector... However I can't see ...
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44 views

How does light manage to change its course at the boundary of two media of different optical densities?

This is a conceptual question. I already know the law of refraction but I need something like an idea of the Physical process from both particle and wave theory standpoints. Why does a ray of light ...
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6 views

Why is forward brillouin scattering difficult to observe?

Generally we talk of only the backward Brillouin scattering. And I just know forward scattering is difficult to observe? Why is it so? Does it have something to do with phonon life time? Is it ...
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32 views

Optical system for cloning an image of a light source?

I need to create an optical system for cloning an image of a light source to human eyes. Is there a correct solution(design) for this problem. Reflectivity of the mirrors must be equal. Because ...
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1answer
53 views

Single particle passing through the double slit at a time [duplicate]

In modern experiments, With the classical setup of photons or electrons passing through double slit, the intensity is kept extremely low, such that one can detect a single particle passing through ...
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148 views

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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24 views

What is the formula of power of an optical instrument?

I have searched and found that the power of a lens, with surrounding medium of refractive index $n$, is $n/f$ where $f$ is the focal length, the formula is $$n/f=(n'-n)/R1 + (n-n')/R2.$$ But in my ...
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Optics modelling software

I am looking for software that could allow me to model the internals of my spectrometer. I would imagine some sort of ray tracer that allows me to add mirrors, slits, gratings etc. This way, I can see ...
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11 views

Point Spread Function of a Complicated Optical System

suppose I image a point source using a single lens, then at its focus (image plain) I'll get a spot resembling a Fourier transform of the point. As far as I know, that is defined to be the lens's PSF. ...
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About Powell lens

I am a Post graduation student and I am doing a project on the conversion of a Gaussian beam into a flat top beam using optical components. I have found that the best component to do the same is a ...
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36 views

What is the maximum of information in a beam of light?

If I look at the space I can see the Andromeda Galaxy as a small dot in the sky. If I look through a telescope, I can see the spiral shape. If the saw right through a huge telescope, I could see a ...
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25 views

Fringe Localisation

How am I to understand where the fringes of a given setup are localised? For example, Young's double slits have non-localised fringes, that is the fringes are localised (and so are well formed) at ...
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Usefulness of half-shade in Laurent half-shade polarimeter

In the Laurent half-shade polarimeter, if the half-shade weren't there, what difference would it make? The light after being polarized by the Nicol polarizer,could have entered the tube containing the ...
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Is it feasible for a lens of focal length of 1 meter to have a radius of curvature of 92.1 meters? [closed]

Is it feasible for a lens of focal length of 1 meter to have a radius of curvature of 92.1 meters?
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What is incorrect about the original statement of Fermat's principle?

Here are some statements about Fermat's Principle taken from Eugene Hecht's Optics book. The original statement of Fermat's Principle : "The actual path between two points taken by a ray of light is ...
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Absortion of light by a plasma

Considering a plasma generated in a fixed volume by increasing the temperature of Helium gas from the environment temperature (this temperature is not stated) and an initial presure of 0.001 Torr, to ...
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What is angular accelerating light?

As described in this article "Our angular accelerating fields rely on combinations of orbital angular momentum - so-called twisted light," says Forbes. Light carrying orbital angular momentum ...
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38 views

Making a bright beam of artificial white light

For educational purposes, is there a way to make a narrow bright beam of white light without much equipment and without using the sun as the source? The collimated beam should be about 2 mm wide for ...
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28 views

Would an inverted design of a laser phosphor display (LPD) work?

Background info... It is my understanding that a laser phosphor display works by emitting RGB laser beams through a mechanism that cycles them in a pattern similar to a cathode ray tube. When I read ...
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Rayleigh scattering question

Usually from books, Rayleigh scattering only refers to the light scattering by neutral atoms or molecules. For example if I want to measure temperature or number density in combustion using Rayleigh ...
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21 views

Criterion for resolvability and spot size for optical systems

Look at the following table: By spot size I mean if we have a point source for the object, the angular radius of the spot created by the source as viewed in the image plane. My question is is all ...
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Fraunhofer Diffraction and Lenses

Suppose we have the diffraction pattern for a single slit in the Fraunhofer approximation. In order to see this diffraction patter at finite distance we locate a converging lens. Is the diffraction ...
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171 views

By what maximum amount can we concentrate sunlight?

This refers to a previous question re: Solar Cell Systems and as part of the answer the statement: If we concentrated sunlight to [the] maximum amount 42600× was given. My questions are: By what ...
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166 views

Increasing the efficiency of solar cell systems

As far as I know, there are currently two main approaches to utilising solar radiation for maximum energy conversion to electricity. These are either direct conversion to electricity, using ...
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23 views

Fabry-Perot Spectroscopy

Suppose you have a source of variable wavelength, and you are sweeping the wavelength while monitoring transmission through a Fabry-Perot cavity at normal incidence? What (qualitatively) could you ...
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Rayleigh length determination for Laguerre-Gaussian Modes

Recently I have measured the Rayleigh length of a Gaussian electron beam probe in a scanning electron microscope, using the function: $$w(z) = w_0 \times \sqrt{1 + (z/z_r)^2}$$ Where $w$ is beam ...
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How to calculate the focal length of spherical shell (zero meniscus lens)

I can get my head around the optics of a spherical shell (a meniscus lens that neither diverge nor converge, being neither positive nor negative etc). I don’t see how I can describe in a formula how ...
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Phase change by reflection [duplicate]

Let's consider a light ray falling on a cuboid made of glass at the angle $\alpha$. Then there will be a reflected ray $A$. The ray will also refract. Let the refracted ray be $B$. Ray $B$ will be ...
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Determining the focal length of a gradient index lens

There are three subquestions in this question, all marked bold. Let's consider a planoconvex gradient index lens of thickness $d$, radius $R$ whose refractive index changes with the distance from ...
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33 views

image transmission through waveguides

in general optics we study the transmission of image information through lenses, basically governed by Fourier optics laws. how can images be transmitted through waveguides at smaller propagation ...
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27 views

Calculating the beating length of the directional coupler

I want to determine the coupling length needed to achieve a certain power coupling coefficient of a directional coupler. Recently, I read a paper titled "Ultra-compact high order ring resonator ...
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1answer
56 views

Why do snorkelers not need to wear corrective glasses when snorkeling with goggles on?

I am myopic ~ -2.75 sph +1cyl. When I went snorkeling they tell you not to wear glasses behind the goggles. Surprisingly, underwater, things remain in focus with goggles on even without prescription ...
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Determining the refractive index of a foil

(59th Polish Olympiad in Physics, final stage, experimental part, 2010) You have at your disposal: a sample of blue foil of a homogeneous material, placed between two glass panes in a ...
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What will my diamond fibre shirt look like?

So, during an idle moment when I mused that our experimental setup would be a lot less hassle if it was made from a 1kg single crystal of diamond, this thought occurred to me... Since single crystal ...
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What is the “Obscuration Factor (OBF)”?

In a paper I am reading for my master thesis I came across this "obscuration factor (OBF)". The authors indicate that it is a measurement of the average intensity of reflection. They do not give a ...
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17 views

Design process of directional coupler

I know that when two wavegudies are brought sufficiently close enough, the electromagnetic fields overlap and light can be coupled from one waveguide to the other. However, how to calculate the ...
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101 views

Why is there a negative sign in front of the optical wave?

In undergrad I lost (a lot) of marks in my optics class for writing: $$A(t) = \exp(i(\omega t + \phi))$$ Instead of: $$A(t) = \exp(i(-\omega t + \phi))$$ In a derivation where I must have needed ...
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Interference and windows

The other day i was learning about interference patterns with the effect of a bubble making a rainbow on the surface. I learned that the reflections from both sides of the soap can interfere ...