Questions tagged [optical-materials]
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286 questions
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Why is Al2O3 so popular in plasmonics?
I've tried to find my own solution for this question and found out that
It is cheap
It is an insulator
It efficiently absorbs UV
Are there more properties that makes it so popular?
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Why does aluminium-on-glass mirror work without distortion?
I have read an article about glass (zerodur) with low thermal expansion coefficient. It is mentioned that large casts of such glass are covered with reflective layer of Aluminium and used as mirrors ...
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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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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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Why does the refractive index not mirror the Lorentzian peak shape of the absorption index?
In the characterization of materials, there are many methods used: One of them is infrared spectroscopy. In a lab we saw the indices of refraction and absorption of a certain (semiconductor) solid ...
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Why grating is an essential part of a monochromator?
From looking at these two images, it appears that the dispersed "rays" of the reflected light could be manipulated just as well if the reflecting mirror would be turned to a fixed angle. So why is ...
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Why does a glass acts like a mirror in viewed at an angle? [duplicate]
There is a conference hall , glass door parallel to my desk. whenever the door is open, I can see reflection of images perpendicular to the viewing angle. But when the door is closed, I can’t see any ...
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Crystal field in diamond
The crystal field effect occurs in ionic crystals and causes a splitting of the magnetic quantum levels of the cation. The magnitude of the splitting may be roughly computed by obtaining the potential ...
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Emissivity of vacuum for radiation heat
What is the heat radiation emissivity of vacuum? For air as well? What is the difference?
I understand that the vacuum has reflectivity of 0, So what is the other two values are in
$$
reflectivity + ...
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Plasma frequency
I have a neutral plasma and I need to solve Maxwell equations given the charge and current densities on the plasma. In order to do it I need to know the electrical permittivity $\varepsilon$, I've ...
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How to calculate the Gain of EDFA amplifier? [closed]
I have co-propagating pump laser and tunable optical signal and I want to measure the Gain of EDFA Amplifier from the Optical Spectrum Analyser (OSA). I have measured first the signal power without ...
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What is the principle behind the use of one LASER for optical pumping of Rubidium in presence of magnetic field?
How can we use a single LASER for optical pumping of rubidium in the presence of magnetic field as the zeeman levels are degenerate in the presence of magnetic field and how to decide upon the ...
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Is there a (cheap) optical resonance demonstration using visible light?
I'm looking for a impressive, inexpensive lecture demonstration of optical standing wave resonance. Preferably visible light. Can anyone suggest such a demo?
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Defects of smart glass (electrochromic glass)?
Smart glass is a type of glass that uses electrochromic mechanism to change it's light transmission properties in response to voltage, and it's made by sandwiching certain materials between two panes ...
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What are the factors affecting transparency and color of a substance [duplicate]
What is the reason behind visual properties like color and transparency of different substances? I have always heard that the structure of the substance is responsible for these properties. I always ...
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Why does optical media have different refractive indices?
Optical density is a measure of the refracting power of a medium. In other words, the higher the optical density, the more the light will be refracted or slowed down as it moves through the medium. ...
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Optical signal filters
Are there any optical filters which filter the signal's frequency and not based on the wavelength of the light? So what I mean is, if I have a modulated/pulsating light signal riding on a large DC ...
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Optics, What is a Foil?
I was using a program for simulating optical elements; mirrors, gratings, foils, crystals, slits, and zoneplates are what it mentioned. Does anyone know what a foil is in terms of optics? I know what ...
user24082
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Are all fluorophores dipoles?
Lately I'm reading about surface enhanced fluorescence. In many articles I can see that fluorophores are called "dipoles". Is it because that they can be modelled by a vibrating electric dipole? Or ...
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Anodized aluminium reflectivity at 10.6 um
I wonder how I can model anodized aluminium reflectivity in ray tracing-based optical simulation. I know that the parts my company is using are anodized to get covered with a ~20 um (as specified) ...
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What are the current experimental limits on the polarizability of the vacuum?
Many (all?) materials are polarizable at some level; meaning that when we apply an electric field across the material, there is an induced dipole moment
$$
\vec{p}=\alpha(\omega)\vec{E},
$$
where $\...
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How can fiber optic image conduits consist of only fiber core, no cladding?
Looking at fiber optic image conduits, I found that they have a packing fraction (the ratio of the fiber core's area to the total area) of 100% (source here).
In other words, they consist only of ...
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Visible light through a single-mode optical fiber?
If I understand things correctly, the optical fibers used for (long-range) data transmissions are generally single-mode fibers, transmitting light in the 1300-1500 nm spectrum.
Now, could such a ...
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Minimum seperation between two Airy disks as a function of the distance between two point sources of coherent light passing through the same objective
I have two coherent point sources of light, $A$ and $B$, separated by a distance $L$, which I focus down to the diffraction limit using a high-powered objective (e.g. a $\approx 100x$ objective). If ...
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Is it possible to make an optical lense that is an analog to a gravitational lense?
There are many lenses that do all sorts of things. eg. horshoe lenses twist light, meta material lenses can boggle the mind.
Is it possible to make an optical lense that is an analog to a ...
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Temperature-induced wavelength shift of optical coatings?
Optical coatings designed for reflection or anti-reflection are made of many thin layers which will expand when heated. What will the effect be on the wavelengths the coating will reflect when the ...
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Electrooptic Tensor, Relating Tensors to Orientations
So I'm trying to gain a better understanding of electrooptic tensors:
An example of a quartz electrooptic tensor is given.
I know in order to best implement this crystal, in order to get the highest ...
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Creating small polarised scientific lenses?
How would I go about creating small polarised scientific lenses?
Thinking 5mm by 5mm, with a light-source behind it for the purposes of reducing (polarised) surface reflection (assisted with a cross-...
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Optical Waveguide's "Base Bandwidth"
Consider a dielectric slab waveguide (lossless, isotropic) illuminated transversally from the vacuum (with coherent, monochromatic light).
We define the base bandwidth of a waveguide (or optical ...
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Depolarisation of Light in Optical Fibre
I have a question for which I can't seem to find a solid answer in literature and wondered if anyone could offer advice or reliable references please:
How does light depolarise in non-polarisation-...
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What is optical confinement?
What is optical confinement? What is it intuitively? How does this 'optical confinement' affect the performance of a laser?
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Why are there direct bandgaps?
This Question has been bugging me for sometime. Some semiconductors have direct bandgaps and indirect bandgaps. So what causes a direct bandgap to occur? The physics behind ,why there are direct ...
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Twisted Nematic liquid crystal: extent of degradation due to DC drive?
It is commonly accepted wisdom that a Twisted Nematic LCD must always be driven using AC instead of DC, because DC will supposedly denature the LC. I have two questions:
Does this effect only happen ...
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Slowing down light in an opaque crystal for a whole minute
I just read about a team of physicists at the University of Darmstadt, Germany, that managed to completely slow down a beam of light that traveled through an opaque crystal (article here).
How is it ...
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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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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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