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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How can I estimate the elasto-optic coefficients ($p_{11}$ and $p_{12}$) of a material?

I am attempting to estimate the elasto-optic coefficients ($p_{11}$ and $p_{12}$) of $\mathrm{TiO}_2$ and $\mathrm{ZrO}_2$, where $p_{11}$ and $p_{12}$ refer to the elements of a strain-optic tensor ...
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550 views

Boundary Conditions Invariant Under Conformal Transformations in Electrostatics?

in two dimensional electrostatics it is assumed that the whole physical system is translationally invariant in one direction. Here, the two-dimensional Laplace equation $$\Delta \phi(x,y) = ...
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242 views

Why is $\textbf{D}$ the response to $\textbf{E}$?

In the text Wooten, equation 2.69 shows $\textbf{D}$ being the response to $\textbf{E}$ with $\epsilon$ as the response function: $$ \textbf{D}(\textbf{r},t) = \int d\textbf{r}^{\prime} \int ...
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Examples in which the light maximizes the optical path length

I posted a similar question about geodesics on Math.SE. Many sources (Wikibooks for instance) claim that the light could maximize the optical path length in some cases. But I don't think it's actually ...
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297 views

Reconciling total internal reflection and the evanescent Wave

I understand that light is guided in a dielectric waveguide via total internal reflection. My question is regarding the origin of power contained in the evanescent field traveling along the direction ...
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980 views

The skin effect and the reflectivity of gold

I am simulating a waveguide in COMSOL, a FEM solver. My model looks like this (it is similar to a standard Quantum Cascade Laser geometry): Therefore there is a very thin (30nm) layer of gold ...
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313 views

Can solar furnace achieve higher temperature than sun surface? [duplicate]

Can solar furnace achieve higher temperature than sun surface? I guess not, but I'm not sure about that. Can you check my reasoning: -------- My reasoning ----------- Consider Sun as a black body ...
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135 views

3D coherence of light speckles- difference between Airy and gaussian speckles

In this article, http://www.dfm.uninsubria.it/laboferri/web_page/articoli_pdf/PRA_2009-Magatti-Three_dimensional_coherence_of_light_speckles-experiment.pdf, the 3D-coherence properties of light ...
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556 views

How do I use the electro-optic tensor?

I would like to calculate the performance of an optical phase modulator, in which a varying electric field across a crystal modulates the effective refractive index of light passing through the ...
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2k views

Converting between brilliance, intensity, and flux

This one should be a bit of a softball, but I can't find it explicitly stated anywhere on the internet, and my basic unit analysis doesn't seem to work. Suppose you have a beam of synchrotron ...
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175 views

Is this wave spatially coherent?

Is the following wave (the solid lines representing the intensity maxima) spatially coherent? I've been seeing different, seemingly contradictory definitions of spatial coherence. Some places ...
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204 views

How would we see the earth if refraction of light was significantly stronger?

On worldbuilding.SE there is a question about the cosmological consequences of a world with super-high refraction and atmosphere opaqueness. I'm assuming the easiest way to minimally change the laws ...
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158 views

At Interfaces Does Light Have to Accelerate?

First, I'm not sure if photons have to "get up to" the speed of light, or if they are thrown into existence at that speed. I know that they should just be generated moving at their speed, and I know ...
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Is optical-illusion responsible for Loch Ness monster? [closed]

When you look out at the white-caps on a wind-swept lake, you can see a dark, undulating pattern under the crests of the white-caps. Could this shadow-like area explain the sightings? Revised, see ...
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903 views

Is antumbra part of shadow darker than penumbra part of shadow?

I'm exploring different types of shadows casted by objects. I want to know if antumbra part of a shadow is darker than penumbra part. I've found two misleading pictures on Wikipedia: First: Second: ...
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How to bend light?

As we all know that light travels in rectilinear motion. But can we bend light in parabolic path? If not practically then is it possible in paper? Has anyone succeeded in doing that practically ?
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Can spectacles converge sunlight to an extent that it burns the eyeball?

I need to know whether wearing spectacles can cause optical harm. I saw a movie where one pair of glasses was placed on table exposed to sunlight, then the sunlight converged and focused to a point ...
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Difference Between Fraunhofer and Fresnel Diffraction

What is the difference between Fraunhofer diffraction and Fresnel diffraction? I mean diffraction is just bending of light waves or waves in general around a point. So how can there be two types of ...
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How much light can pass through a point?

Analogy: an infinite number of lines can pass through a point. Is there a limit on the number of lasers that can pass through a point? Obviously, with lasers the “point” would be a sphere with the ...
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Optical explanation of images of stars?

Very often when viewing pictures of the cosmos taken by telescopes, one can observe that larger/brighter stars do not appear precisely as points/circles on the image. Indeed, the brighter the light ...
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What does an atom radiate: a wave packet or a single photon?

What does an atom radiate: a wave packet or a single photon?
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Why are color values stored as Red, Green, Blue?

I learned in elementary school that you could get green by mixing blue with yellow. ...
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490 views

How do you calculate power at the focal point of a mirror?

I'm a Mechanical Engineering student and I'm working on my senior project, so I need help. My project is about designing a solar dish having a diameter of 1.5 meters and a focal length of 60cm. so at ...
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Focusing Light with Flat Mirrors

What is the best way to focus (sun)light using flat mirrors? My goal is to start a fire. Cutting the mirrors is easy.
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Why is an opaque body opaque?

When does a body qualify to be called an opaque body? Is it anybody which cannot let visible light through it or is there any other definition? And when and how does a body allow radiations through ...
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284 views

Visibility of moon-based laser from Earth

If someone (or some robot) on the moon were to point a laser at the Earth, how many watts would the laser need, to be easily seen with the un-aided eye from Earth? Obviously this depends on a number ...
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Focusing and collimating laser light on a table top scale

I am looking for a summary of practical methods of focusing and collimating laser light, which I guess are contradictory objectives, or are they? For example, when I use typical small diode lasers, ...
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Why does the colour of a thing change when under huge magnification?

For instance, this image: shows human eyelashes close up. The lashes look green, in fact the whole surface area has a strange tint of green Why is this?
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Laser beam shaping

Hi I like to build a laser pointer that reflects different shapes for a project I am working on. I know this can be done with Diffractive Optical Elements. Are there other options? DOEs are expensive. ...
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how does a sniper scope work?

How does a sniper rifle scope enables us to pinpoint the exact location even though the lens in situated 5-6 inches above the muzzle. The bullet leaves the muzzle and hits the target exactly where the ...
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372 views

Dark matter is electrically neutral

I would like to know how come if dark matter was electrically charged it would reflect light. What are the equations or the logic behind it?
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Distance of objects in car mirrors

We've all seen that label on our passenger side mirrors that says, "Objects in mirror are closer than they appear." Why is this? Further, why does it only apply to the passenger side mirror, and not ...
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309 views

Infinite total internal reflection

Suppose that I have a block of some transparent material, glass, for instance, with a certain index of refraction. Suppose that the transparent material is placed in air or in any other transparent ...
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226 views

Light Polarizer and the Second Law of Thermodynamics

I have stumped myself with a thought experiment of my own devising. Suppose I take a beam of wholly depolarised, but otherwise plane wave light. Its von Neumann entropy per photon is $\log(2)$ nats ...
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How would an X-ray mirror work?

I was wondering if light can be reflected how can someone reflect X-ray of what material does it need to be made of and is its design completely different to that of our original mirrors? Does this ...
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Will a prism widen a monochromatic beam?

The representation of the experiment which demonstrates that white light consists of many colors, invariably shows that the beam of white light is broadened inside the prism and is some what more ...
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842 views

Why does light diffract only through slits?

We can see diffraction of light if we allow light to pass through a slit, but why doesn't diffraction occur if we obstruct light using some other object, say a block? Why are shadows formed? Why ...
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Three polarizers, 45° apart

If light is passed through two polarizing filters before arriving at a target, and both of the filters are oriented at 90° to each other, then no light will be received at the target. If a third ...
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Can anyone explain to me why light is not dispersed into a spectrum through a parallel glass slide, but only through a prism?

The question pretty much sums up what I need to know. Why is it that light only gets dispersed into a spectrum when travelling through two non-parallel sides(like a prism) and not through something ...
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239 views

Why can't we perfectly focus light-abberations aside

I don't understand why there is necessarily a diffraction limitation on optical systems. Where does this limitation in focusing light come from?
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497 views

Where in the atmosphere is the blue light scattered?

I have searched Wikpedia and the Physics Stack Exchange archieves, and I cannot find the answer to these two related questions. If it is, please guide me to where this information is located. If ...
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207 views

Why is night vision lacking color?

When I look through night vision with a video camera or see it in movies it always seems to be sort of grey or white. Why doesn't night vision have color?
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Possibility of making an experiment in a classroom to simulate DNA diffraction

I am a TA in a structural chemistry class. The professor want me to show students how Watson and Crick determined the structure of DNA from X-ray diffraction results of DNA crystals. The professor ...
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Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?
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How does light know which path is fastest?

We know from Fermat's principle of least time that light follows the fastest path. But how does light know which path is the fastest?
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A telescope with a bunch of small mirrors

Together with colleagues we got this question. Imagine to take small mirrors, the size for example of a dentist mirror, and stick them to a wooden frame with a parabolic shape. Each mirror is flat, ...
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What is the difference between surface plasmon and surface plasmon polariton?

I'm trying to understand this reading article linked below and I still don't know how to explain this simply, without need to derive everything mathematically. Can someone just write here how do SP's ...
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Optics alignment of a confocal scanning microscope

I am facing a challenge in my project regarding optical alignment. See the figure: The challenge is with the vertical optical system alignment. I considered placing a mirror and check back if the ...
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409 views

How are X-rays focused? Specifically in XRD. Well do they even focus X-rays in XRD?

I read in a government website that reflecting an x-ray from a parabolic mirror followed by a reflection from a hyperbolic mirror results in focusing the x-ray, but this was for astronomical purposes. ...
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How do “holographic plates” work?

I asked a question about laser stage lighting over at Audio Video Production, and received an excellent answer that explained that laser clusters are generated from a single beam via something called ...