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Photonic band gap materials as astronomical filters

Photonic band gaps are created when materials (at least 2) of different refractive index are stacked on top of one another. If the thickness of these alternating layers is exactly right, these materials act like optical band passes i.e allowing only a certain portion of the optical/electromagnetic spectrum to pass through them. I was taught this last year as part of a course on Optics & Photonics. And now, almost an year from when i was taught this, i realize how they can be applied in astronomy.

Astronomical filters, such as the Johnson UBVRI or the SDSS ugriz, are lenses which act like band passes. The band structures of UBVRI and the ugriz are shown.

source :

Coming back, the idea is to look for a photonic band gap material which can be used as an astronomical filter. But before that, i needed to know what the actual composition of filters are! And this was harder than i thought. Google and wikipedia were of no help and i couldn't find anything on ads either. Then i realized that the companies that manufacture these filters probably patent them to be able to sell/profit from them. So i started searching google patents for filters and voila! I found two links here and here, referring to two types of filters that seem to vaguely resemble two component photonic band gaps.

A simple google search for "photonic band gap band pass" will show you the kind of band passes to expect - 

source :

I need to brush up on how to simulate the band pass i.e transmittance vs wavelength/frequency characteristics for various photonic band pass systems. And i need time. Some more time...

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