Mirror created to understand more about Universe’s beginnings
3 Jan 2017 by qwbdchbctt.d qwbdchbctt.d
An international team of astronomers and engineers have created a magnetic mirror that could be used to detect gravitational waves.
An international team of astronomers and engineers have created a magnetic mirror that could be used to detect gravitational waves.
The device is the result of collaborations between institutions backed by the European Space Agency (ESA) to develop technologies necessary for future space programmes. The device is able to detect B-mode polarisation from the cosmic microwave background – believed to hold information about primordial gravitational waves.Professor Giampaolo Pisano, from Cardiff University and first author of the paper, said: "We, like others, have been working for over two decades on the development of technologies that would enable the detection of the B-mode polarisation. This has proven to be a challenging problem because only a tiny part of the overall signal exhibits this polarisation.”
A key component for detecting B-mode polarisation is a half-wave plate, which is used to modulate the polarisation of electromagnetic radiation. By rotating the half-wave plate, the polarisation of the radiation also rotates, created an oscillating pattern that can be easily determined from unpolarised radiation.
A common issue with these half-wave plates is that they have a very narrow band of frequencies they can modulate, making them unsuitable for use in space-borne instrumentation. By using metamaterials – manmade materials engineered with features not found naturally – Pisano and a team of researchers were able to create a magnetic mirror, which they then combined with a polarising wire grid.
The 20cm prototype device operates from 100 to 400 gigahertz with more than 90% efficiency. The researchers believe with some adjustments they can achieve both greater bandwidth and higher efficiency.
Currently, the researchers are developing a 50cm version, with a final goal of developing a device more than a metre in diameter for the Cosmic Origins Explorer, a ESA mission to survey microwave polarisation of the entire sky. It aims to probe cosmic origins, neutrino masses and the origins of stars and magnetic fields.
The study was published in Applied Optics.
