PDA

View Full Version : Can Nano-antennas (optical antennas) be used as telescopes?



mapreader
2012-Feb-29, 06:42 AM
There's been a lot of hype over using the newly developing technology of nano-antennas (nantennas, optical antennas) for solar power. They're made from carbon nanotubes and are small enough to treat light the same way a radio receiver treats radio waves. A solar panel of nantenna arrays would be able to absorb up to 95% of light (compared to around 20% now) and then directly convert it to electricity or store it. it also holds a lot of promise for other fields such as television.

I'm wondering if it's possible to use a nantenna array as a space telescope. If we could, would it be more efficient than our current lens-based telescopes?

I'm particularly interested in the implications for interferometry. To build a high resolution interferometer for visible light or infrared requires high degrees of accuracy to line up the light beams. An interferometer in space would require formation flying at such a high level of precision that I doubt it's possible. Radiowaves being captured by radio antennas, on the other hand, can be absorbed separately and combined later. That's why radio antennas all over the world can sync up and don't have to be in line.

So would an optical antenna that interacts with light the same way regular antennas do with radio-waves make a great interferometer? You could position such arrays millions of miles apart in space without having to worry about lining them up. It would seem that such a development would have a huge impact on astronomy.

Nantenna arrays are due to be scaled up in production in the next few years and are projected to cost $420 per square meter (which I imagine would go down over time).

antoniseb
2012-Feb-29, 02:29 PM
The technology to implement this as a telescope is pretty far outside what is foreseeable. You'd need to track the energy and phase of every single photon, and coordinate that into an image. There may be other obstacles. At the moment, there is a fairly interesting device being tested at Mount Palomar which is a superconducting sensor that is very efficient at collecting photons, that also can sort them into relatively narrow bins energy-wise (within 2%). This is not cheap, but it answers one of your hopes for these antenna arrays.

mswhin63
2012-Feb-29, 03:16 PM
I have seen a couple of science papers recently on these new antennas and I too was considering whether these could be used in the way you mentioned. I am studying first year Uni so as I go through my course I may look at these in the right time for interferometry. That if technology doesn't change by that time.

In my technical capacity (yes I am qualified in the service industry) one of the problems will be receiver technology which would have to be developed under the same conditions as the antenna. I suppose if they can make antennas in nano scale it would be possible to continue with electronics components in the same manner.

Malcolm


There's been a lot of hype over using the newly developing technology of nano-antennas (nantennas, optical antennas) for solar power. They're made from carbon nanotubes and are small enough to treat light the same way a radio receiver treats radio waves. A solar panel of nantenna arrays would be able to absorb up to 95% of light (compared to around 20% now) and then directly convert it to electricity or store it. it also holds a lot of promise for other fields such as television.

I'm wondering if it's possible to use a nantenna array as a space telescope. If we could, would it be more efficient than our current lens-based telescopes?

I'm particularly interested in the implications for interferometry. To build a high resolution interferometer for visible light or infrared requires high degrees of accuracy to line up the light beams. An interferometer in space would require formation flying at such a high level of precision that I doubt it's possible. Radiowaves being captured by radio antennas, on the other hand, can be absorbed separately and combined later. That's why radio antennas all over the world can sync up and don't have to be in line.

So would an optical antenna that interacts with light the same way regular antennas do with radio-waves make a great interferometer? You could position such arrays millions of miles apart in space without having to worry about lining them up. It would seem that such a development would have a huge impact on astronomy.

Nantenna arrays are due to be scaled up in production in the next few years and are projected to cost $420 per square meter (which I imagine would go down over time).

cjameshuff
2012-Feb-29, 06:00 PM
The difficulty with optical interferometry is largely due to the short wavelengths in the visible and infrared. It's much easier to achieve accuracy within fractions of a wavelength when the wavelengths of interest are in the range of centimeters or meters instead of hundreds of nanometers. Optical antennas do nothing to help here...in fact, an optical antenna array will most likely be far more difficult to fabricate than a precision mirror.

Handling signals at optical frequencies is another problem. It's just not feasible for electronics to operate at such frequencies, and while optical antennas can help direct light to a more conventional sensor, such sensors can't preserve the phase information necessary for doing interferometry. The best way to handle such signals is to do it optically.