Questions tagged [optical-materials]
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152
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1answer
39 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 ...
0
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1answer
41 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.
2
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1answer
52 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 ...
1
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0answers
17 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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0answers
22 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
22 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....
1
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1answer
29 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 ...
0
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0answers
45 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?
1
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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 ...
4
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2answers
86 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 ...
4
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0answers
37 views
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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14 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 ...
1
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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
101 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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0answers
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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0answers
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 ...
1
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0answers
29 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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0answers
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 ...
0
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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....
0
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2answers
46 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
48 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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0answers
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 ...
0
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1answer
91 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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93 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 ...
0
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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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0answers
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 ...
3
votes
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 ...
0
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1answer
78 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 ...
0
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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
49 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
192 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 ...
1
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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 ...
1
vote
1answer
80 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.
17
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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 ...
1
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1answer
49 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 (...
2
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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
145 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 ...
2
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1answer
76 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
58 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 ...
3
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2answers
147 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 ...
1
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1answer
247 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
57 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.
1
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2answers
470 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?.
1
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0answers
157 views
Change of refractive index using semiconductor
I was wondering, if it is possible to change the refractive index of a semiconductor using an electric field or current? I have heard about injecting charges to tune the refractive index. How/Why does ...
2
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2answers
3k views
What plastic-like materials allow IR to pass through them? [closed]
What plastic-like materials allow IR to pass through them?
Material should be solid and plastic like. Does't care if it is transparent to light or not.
IR ray is emitted by Sharp distance center so it ...
2
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3answers
186 views
See through material for IR camera
I have an IR camera that I'm trying to hide behind an opaque or fine meshed material (plastic?).
Any idea?
Thanks!
