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Questions tagged [optical-materials]

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6 views

how does graphene on silicon chips allow optical control?

I got in from this link: https://www.nature.com/articles/s41598-017-16989-9 although I don’t complete understand the idea ...
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1answer
27 views

Does diffraction depend on refractive index of a medium?

Does diffraction pattern depend on refractive index of a medium? Does the transmitting media influence on difraction the phenomenon or is it caused by light and the edge alone? Is a diffraction ...
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1answer
41 views

Classical (non-quantum) explanation for the transparency of glass?

Is there a classical explanation for the transparency of glass? How did physicists explain the transparency of glass before quantum mechanics?
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10 views

Question about adjusting focus on augmented reality

I am working on a project and I am trying to build augmented reality glasses. I have a question about focusing the projection from screen and the real object on the far distance at the same time. How ...
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1answer
54 views

What is the physics behind Samsung Galaxy Axx-series “3D Glasstic”?

How does back cover of Samsung Galaxy A30 transform light into those wavy white lines? I hope you could draw a schema of incident and reflected light with the answers.
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1answer
55 views

Focal plane of ideal thin lenses and spherical mirrors

Recently I was studying about optical instruments and in my book I came across a point which stated that When non axial parallel rays are incident on an ideal spherical mirror at a small angle or a ...
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22 views

Reflection coefficient phase using Kramers Kronig, formula equivalence

Why are the following two formulas for the phase of the reflection coefficient equivalent (according e.g. to [1])? \begin{align} \Theta(\omega_0) & = - \frac{\omega_0}{\pi}P\int_{0}^{\infty}\frac{...
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24 views

How does light pass through any glass? [duplicate]

This might be a very stupid question for Science students, but I had this doubt always, since childhood. I still don't understand even when I'm adult because I didn't read science in detail. When I ...
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1answer
24 views

How to design material to avoid (light) reflections?

I wondered how a material (maybe for example a glass window) must be made to provide none or very few reflections. And while I think about it I don't really know which interaction is behind reflection....
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1answer
34 views

How to derive the macroscopic dielectric function?

I'm following Matteo Gatti's slides to repeat the derivation of macroscopic dielectric function $\epsilon_M$: $$\epsilon_M=\dfrac{1}{\epsilon^{-1}_{\vec{G}=0,\vec{G}'=0}(\vec{q},\omega)}.$$ On page ...
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46 views

Need an IR transmitting plastic that is white in color and partially opaque to visible light?

I need an IR transmitting plastic material (85% or better) that is white in color, but partially opaque to visible light. Does anyone know of such a substance?
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1answer
38 views

Effect of IR absorption on visible region refractive index of Glass

If we go with the Lorentz oscillator model of susceptibility, it is obvious that high frequency resonance tails raise the refractive index of low frequency light. However, I recently came across a ...
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2answers
90 views

Are there any real-world examples of refraction of light by magnetic permeability?

The question Fresnel Transmission Coefficient for Magnetic Field is interesting. Thinking about it led me to reflect upon what little I know of the history of optics, with refraction by lenses and ...
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Difference between permittivities eps-opt and eps-inf?

Very often in materials physics we are interested in the relative permittivity at optical frequencies, which is usually denoted by $\varepsilon_\text{opt}$ or $\varepsilon_\infty$. But I'm confused ...
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15 views

Why does the images of slit slip down in bottom as we move the lens?

Why does the images of slit slip down in bottom as we move the convex lens in the experiment of "determination of wavelength of sodium light by fresnel biprism experiment". We made the system coaxial ...
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1answer
24 views

Dielectric properties of polarizing beam splitter

Are all polarizing beam splitters made up of dielectric materials?If so, what kind of dielectric materials are actually used to make them?
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3answers
106 views

Reason for change in colour of light

We all know that light has constant speed, and variable wavelength, and frequency. Suppose I have a big red glass square sheet. When white sun rays pass through it, their colour changes from white to ...
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31 views

How I can add lenses stacked on front of iphone camera to increase magnifying power?

How we can stack different lenses to increase magnifiying power of a smartphone camera? Is there any way to test if stacked lenses will focus light on image sensor of smartphone exactly right before ...
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35 views

Polarizing Beam splitter

What could be the effect of aging in Polarizing Beam Splitters? Is it possible that the Axes for s-polarization and p-polarization change due to some environmental effects on a polarizing beam ...
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0answers
32 views

What is a Material Called that Translates the Image of a Touching Object's Surface?

What is the name of a material that moves light through it in such a way that it appears that the surface of an object has translated through the material? Also, what is an example of this type of ...
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32 views

For the high-frequency permittivity of a material, do I need to look beyond its value in the optical energies region?

I was trying to find $\varepsilon_\infty$ for InSb, and the value I found on Kittel p. 416 was 15.6. But in the literature, even at 6 eV, $\varepsilon (\omega )$ is still in the negative (at -3.835) ...
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1answer
29 views

Does optical density depend upon concentration of a solution?

Does optical density vary upon the amount of salts dissolved in water?
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9 views

Why the first ring's radius appears to be too little in newton's ring experiment?

In newton's ring experiment we should be going to see a large number of rings with their converging radius. But the ring right next to dark fringe is way nearer than 2nd or 3rd which appears to be an ...
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1answer
35 views

What materials allow $12\,\mathrm{\mu m}$ LWIR to pass?

What commonly available materials will allow Infrared Radiation with wavelength of $12\,\mathrm{\mu m}$ to pass through? Commonly available is something that can be obtained easily for manufacturing....
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2answers
49 views

Why is it important to measure permittivity and permeability complex of materials?

I know that in general, $\epsilon(r,\omega)$ and $\mu(r,\omega)$ are complex tensors, so now how do you resolve maxwell equations? I don't understand why there are techniques to measure them if you ...
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2answers
49 views

Polarised glasses for high astigmatism and myopia [closed]

So I have -4 for both of them, which results in -8 in total (same for left and right eye). At my optician, I have to choose the best package they have to make sure my sunglasses can be as light as ...
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11 views

Semiconductors with low thermal conductivity (lattice matched to GaAs)

What are the semiconductors with lowest thermal conductivity that can be grown on GaAs with the least possible incorporated strain (i.e. lattice-matched or close to it)? GaAs has thermal conductivity ...
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1answer
95 views

Can light in a medium travel faster than speed of light $c$ in vacuum?

Refractive index of medium $m$, $n_m$, is given by $$n_m = \sqrt{\mu_r\epsilon_r}$$where $\mu_r$ and $\epsilon_r$ are permittivity and permeability of the medium respectively. And, velocity of light ...
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1answer
29 views

Cooling photons to a solid state

Can we cool photons so the stop moving completely? So they can behave like particles in a solid.
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101 views

A simple thin-film transmittance calculation problem

I am trying to reproduce results of thin-film transmittance given in this article by using this online thin-film calculator tool (www.filmetrics.com). I would like to use the calculator later for more ...
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1answer
43 views

Why does certain clear plastic have an inner glow?

A type of plastic used in packaging for tamper resistant seals appears to have (what I can best describe as) a purplish inner glow under sunlight, and perhaps other bright light. In the image below, ...
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15 views

Spectrum of Dielectric Function along Energy

What do the peaks and troughs in the spectrum of the dielectric function (real and imaginary parts) along energy indicate? I understand that the real part represents the polarization and the imaginary ...
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1answer
40 views

Why air spacing for high power beam splitters?

Ordinary glass cube beam splitters are constructed with a dielectric or hybrid coating on the hypotenuse of a right angle prism which is then cemented to another right angle prism. These fail in ...
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1answer
92 views

How to calculate the dispersion parameter of a Fiber?

I am writing a presentation about DCF Fibers. From many articles i am reading, the dispersion parameter of Fibers are given. But it is not shown how it has been calculated. For example ,in this ...
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1answer
33 views

What is the gain control technique used in optics?

In optics, it is said that The gain bandwidth and gain flatness of Amplifiers are enhanced utilizing gain control techniques.What techniques are they referring to ? I know the automatic volume ...
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1answer
50 views

What is a pump reflector?

I understand the meaning of laser pumping. But i don't understand what is a pump reflector. As a clear definition does not appear online. In the paper,DESIGN AND DEVELOPMENT OF WIDEBAND HYBRID RAMAN/...
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2answers
207 views

Magnifying power of a microscope for a farsighted person

I was doing some problems on optical instruments and in one of the questions it was asked that if a simple microscope(magnifying glass) has a magnifying power 5X for a normal relaxed eye.. what will ...
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1answer
29 views

Which transparent material alters light the least?

I am making a spectrometer as my school project. It's main application will be analyzing the light emitted by various light sources. It measures visible, near IR and UVA/UVB radiation. I need it to be ...
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2answers
89 views

Why can't ultraviolet light pass through glass?

What factor determine whether a body behaves like a transparent object for EM waves of a particular frequency?
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1answer
82 views

Why glass is considered as an opaque body…? [closed]

We know that the transmissivity of glass is 0 then also in general conditions it is taken as an opaque body and also in some books, it is taken as an opaque body.
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1answer
1k views

How can the refractive index be below 1 in a dielectric?

Upon checking the optical properties of different dielectrics, I found the interesting case of $Al_2O_3$. It seems to be reported with a refractive index below 1 in the infrared range of $10 - 12~\mu ...
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1answer
51 views

Is it possible to have an optical version of a greenhouse? With optical fibers?

Optical fibers transport light within them using internal reflection, but the light only enters from one end of the fiber. Is it possible to somehow have light entering from the sides of the fiber (...
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2answers
109 views

Is there such a material that only emits, or “sends out” the same color light that was “taken in” (absorbed)?

For example, glow-in-the-dark materials (photoluminescent) only emit a green hue regardless of the color of the light shone on the material. Is there such a material that emits the color of the light ...
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2answers
148 views

Star Trek - Transparent Metals Possible?

Is the concept of transparent metals (like the transparent aluminum in Star Trek IV - Voyage Home) a real-life concept? Or is it far-fetched movie fiction? Thus my main question then is: could we ...
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1answer
80 views

Is there a material that allows light to pass perpendicular to the surface, but reflects at an angle?

This is inspired by Michael Steven's new video about optics. He shows off Selenite, which has the property that light entering on one side travels perpendicularly down the crystal until it exits the ...
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2answers
59 views

Using of optical slit for different spectrum

Here below the 3 spectrum currently used in astrophysics and illustrating Kirchhoff's laws (emission, absorption and continuous spectrums),: I just want to know : what's the utility of the optical ...
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2answers
148 views

Can you burn invisible jelly balls with a laser?

Suppose you have some jelly balls with similar refractive index as that of water, like in this video. You put them in water, making it invisible. So, the optical behavior of the balls should be ...
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1answer
260 views

Why does the definition of angular magnification relative to the substended angle of least distence that the eye can see

The angular magnification defined as, angle subtended by image of object /angle subtended by object when 25 cm from the naked eye Consider this. An object is placing 50cm in front of a convex ...
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1answer
59 views

How reflectivity of metals depends on the condition of the surface?

Does it depends on the flatness and pureness of surface. does it change when dust or oxides settle on it.
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2answers
501 views

Is there a way to make infrared pass through metals?

I am curious to know a way that will make infrared pass through metals. Metals are good reflectors of infrared,can we manipulate the wave in order to make them pass through metals?.