Questions tagged [optical-materials]

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1answer
37 views

Is magneto-optic Kerr effect discernible for material with natural optical activity?

Magneto-optic Kerr effect requires a system with internal magnetism or external magnetic field and exhibits, say, circular dichroism for reflection measurements. Natural optical activity can have ...
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1answer
33 views

Are there optical materials with larger mean deviation with little to zero angular dispersion?

The following statement is from Concepts of Physics by Dr. H.C.Verma, from the chapter "Dispersion and Spectra", page 434, topic "Dispersive Power": The mean deviation depends on the average ...
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2answers
52 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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0answers
44 views

How is water athermanous?

My textbook says that water is an athermanous substance i.e. the type of substance which does not transmit any incident heat radiations. But how is that true since water is transparent, light that is ...
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0answers
13 views

Are there elastic materials that are transparent to infrared light?

I am working on a device that I want to be encased in an elastic membrane to allow for articulation and water resistance. This means that all sensors must be inside the membrane. The membrane must ...
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1answer
365 views

The numerical aperture of optic fibre and angle of incidence

First My college book contains the following passage: the angle of incidence (relative to the fibre axis ) can't be too large else the ray would be refracting on the core\cladding boundary and ...
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3answers
57 views

What material absorb IR and let visible light through? [closed]

Beside water, what common materials -- man made or otherwise -- absorb infrared (~800nm-~1100nm) and let visible light through? I think glass IR stop filters absorb, but glass itself reflects IR. IR ...
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1answer
27 views

Colored fringes in optics

What optics principle is responsible for the colored fringes seen in the attached picture?strands of hair reflecting sunlight when held very close to the lens[]1]1
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2answers
627 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?.
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0answers
19 views

Is there an optic which reflects RCP beam and transmits LCP beam, or vice versa?

I'm currently looking for an optic which reflects the right circular polarized (RCP) beam and transmits the left circular polarized (LCP) beam, or vice versa. I prefer the incident angle of 0 deg but ...
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2answers
101 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
64 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
144 views

Reflectivity of metallic surfaces

Can someone please point me to an academically verified web resource/page that tabulates the Reflectivity of various metallic surfaces like gold, silver , aluminum, etc.? I have found a list on ...
4
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1answer
83 views

Why are birefringence materials so rare?

By symmetry, most crystals will show birefringence. But the effect is very minute. So the question is actually, why is the birefrigence effect in most low-symmetry materials so small?
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1answer
44 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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2answers
543 views

What does the refractive index for e.g. alpha mean?

When I look for some materials like https://en.wikipedia.org/wiki/Barium_sulfate and want to extract the refractive index then there is written: (nD)=1.636 (alpha). And sometimes also for beta and ...
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11 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
44 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, ...
2
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1answer
68 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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0answers
24 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
27 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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6answers
86k views

Why is glass transparent?

Once I asked this question from my teacher and he replied "Because it passes light.". "And why does it pass light?" I asked and he said, "Because it is transparent.". The same question again, Why ...
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1answer
95 views

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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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....
4
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2answers
98 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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3answers
143 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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2answers
246 views

Doubt on Transmittance

I have a thin film deposited on a glass substrate, when I measure transmittance (T) of it ,should I use glass or air as the reference glass or air? and why? Regarding these points: for bare glass $T=...
2
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2answers
4k 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 ...
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0answers
52 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
41 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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0answers
190 views

Are there Optical Magnetic Mirrors (OMMs) which reflect via interaction with the magnetic field?

The most familiar mirror relies on reflection from a metal, where the very strong interaction of the electric field component of the EM wave with the conduction electrons produces a reflected wave. ...
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0answers
47 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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0answers
16 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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0answers
33 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
50 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
47 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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0answers
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
30 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 ...
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1answer
36 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
7k views

What color does a transparent object reflect?

We say that an object's color is blue if the object is opaque, reflects blue color and absorbs waves of other colors. What color does a transparent object actually reflect?
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50 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
81 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
12 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
119 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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133 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 ...
3
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1answer
44 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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2answers
893 views

Why does “liquid glass” putty turn cloudy when deformed?

What physical process is taking place to make it look cloudy? What's changing to make it turn back to clear over time? While they seem pretty secretive about the exact composition, but I did find ...