Actually I had asked in another post that "Does infrared rays pass through active shutter glass" but someone just commented that infrared rays dont pass through polarized glass. If infrared rays doesnt pass through polarized glass can someone explain the reason or give reference link to look through.
[Physics] Does infrared rays pass through polarized glass
electromagnetic-radiationmaterial-sciencepolarization
Related Solutions
Beginner's guide to band structure follows. I've taken considerable liberties with the details to simplify this so don't take it too literally!
This is going to seem an odd place to start, but consider filling up the atomic orbitals in an atom with electrons. If you take a noble gas, e.g. Xenon, you'll find each orbital is filled completely with two electrons and this is why Xenon is inert. If you take Potassium instead you find all the lower orbitals are filled with two electrons, but the outmost orbital contains only one electron so the orbital is only half full. This is why Potassium is very reactive.
When you clump atoms together into a solid, the interactions between the atoms spread the sharp atomic orbitals into energy bands. Suppose our solid contains $n$ Xenon atoms, then each band can contain 2$n$ electrons. But each Xenon atom contributes 2 electrons to each band, so the energy bands in solid Xenon are all full. That's why solid Xenon is an insulator. In the case of Potassium all the lower energy bands are full up with 2$n$ electrons, but the top band contains only $n$ electrons, i.e. it is only half full, because each Potassium atom has only 1 electron left over to put into this band. That's why solid Potassium is a conductor.
The position of an electron in an energy band doesn't just determine its energy, it also determines its momentum. If you want to make an electron move so it can conduct electricity you need to change it's momentum, and therefore you need to change its position in the energy band. But when bands are full you cannot change an electron's energy/momentum because there are no free spaces in the band for the electron to move into. That's why filled bands are insulating and part filled bands are conducting.
Now, if you imagine taking your solid and filling up the energy bands with electrons there is going to be a highest occupied band and a lowest unoccupied band. Now the nomenclature can be a little confusing. If the highest occupied band is full (like solid Xenon) we tend to refer to it as the valence band, and the lowest unoccupied band as the conduction band. The energy difference between the bands is the band gap. The reason why we call the lowest unoccupied band the conduction band is because any electrons that get excited into it will conduct; electrons in the valence band won't conduct (because the valence band is full).
But, if the highest occupied band is only part full (like solid Potassium) we call this band the conduction band because the electrons in it can conduct. Strictly speaking the highest band is both the valence band and conduction band, but convention dictates we call it the conduction band. In metals we're usually not fussed about the lowest unoccupied band and the band gap because they aren't involved in conduction of electricity.
Now, on to transparency. When a photon interacts with an electron it transfers it's momentum to the electron i.e. it changes the momentum of the electron. But if you recall from above, you can't change the momentum of an electron in a full band. The only way to change the electron momentum is to hit it hard enough, i.e. with enough energy, to make it jump over the band gap into the lowest unoccupied energy band. So if you measure the optical absorption as a function of energy you find there's little absorption until the photon energy matches the band gap, and the absorption suddenly rises. For many materials the band gap energy corresponds to ultra-violet light, so the solid doesn't absorb visible light i.e. it's transparent. As you say, these solids are also insulators because the same mechanism (change of electron momentum) determines both conductivity and optical absorption.
In metals the lowest occupied band (the conduction band) is only partially full so electron momentum can be changed by any amount you want. That's why metals absorb light (and radio waves etc) very strongly and are opaque.
Incidentally you do get borderline cases. Pure silicon is an insulator, but the band gap is only about 1.12 eV and this is less than the wavelength of red light. So silicon absorbs light even though it's an insulator. Well, it's an insulator in the dark. As soon as you shine light on it the electrons you excite over the band gap conduct electricity, so silicon conducts when you shine light on it.
I hope all this helps. If you want to clarify any of the above please comment.
Very reasonable question. I will try to answer it in an intuitive way.
If you have a scattering medium, photons are reflected in random directions; but when you have a refractive medium, something else happens. The photon is not absorbed and re-emitted: instead, the photon interacts with the electrons in the medium, and since these electrons are somewhat bound to the atoms, a displacement (due to the E field of the photon) results in a restoring force. We can measure the degree of displacement or polarization, and express it in terms of the dielectric constant of the material. If there is a lot of polarization, the dielectric constant is high. And the refractive index can be shown mathematically to scale with the square root of the dielectric constant.
What happens then is that the bound electrons move "behind in phase" with the photon, which results in a phase shift of the EM wave (the original phase of the photon which lost a bit of its amplitude, and a lagging phase of the electron). The photon didn't get destroyed - it got delayed, but maintained its direction.
Now when you have an interface between two materials of different refractive index, and light is incident at an angle to that interface, then a greater phase difference builds up between adjacent beams, which is why light is refracted; but if all the light is traveling through the same medium of constant refractive index, all beams will refract by the same amount and remain parallel.
Which is why you can see through a window.
But if you use ground glass, the surface is no longer flat but has been modified to change the direction - and this results in the image behind the glass becoming fuzzy. The same principle exists in the glass used in many showers (original image from Victoria Elizabeth Barnes's posts on bathroom remodeling:
You can clearly see how the bottom half of the window blurs the image of the trees outside. In the article they call this "pebbled" glass.
Best Answer
Infra-red radiation will pass through a polarised medium just like visible light does i.e. the component at right angles to the plane of polarisation will be blocked. So there's nothing special about the fact the glasses are polarised.
However most materials are only transparent over a restricted range of wavelengths. Optical glass only transmits light with a wavelength from about 300nm to around 2500nm. There's a good article on the optical properties of glass here.
However I think passive 3D glasses are made from conventional polarisers, which are made from a polymer called polyvinyl alcohol. I struggled to find much about the spectra of PVA polarisers, though I found this article that lists some polarisers that work down to 3000nm. So it seems PVA polarisers will transmit at least the near infra-red. However the term infra-red covers a huge range of wavelengths from 750nm - 1mm. I can't think of anything, even air, that is transparent right across this range of wavelengths so everything absorbs infra-red light to some extent.
Generally speaking, ultra-violet light is absorbed because it has enough energy to excite the electrons in atoms and infra-red light is absorbed because it has the right energy to excite molecular vibrations. Visible light has too much energy to excite molecular vibrations, but too little to excite electrons in atoms, so that's why most things are transparent to visible light (and probably why organisms like humans evolved to use it). Most things that are opaque, like say paper or chalk, don't absorb the light but scatter it by multiple reflections at air/solid interfaces. The exceptions are things like transition metal complexes and organic dyes.