WASHINGTON – A group of multi-institutional researchers has developed new metamaterial slabs that will help improve the sensitivity of the telescopes being built at the preeminent Simons Observatory in Chile. The slabs were introduced into receivers for use at the observatory by 2022.
The Simons Observatory is at the heart of an ambitious effort to measure the microwave cosmic background – electromagnetic radiation emitted from the early stages of the universe – using some of the largest and most solemn ground-based telescopes on earth. These dimensions help to develop our understanding of how the universe began, what it is made of and how it became what it is today.
“Simons Observatory telescopes use an ultra-sensitive wavelength camera to measure the large footprint with unprecedented sensitivity,” said lead author Zhilei Xu of the University of Pennsylvania. used in the camera to capture environmental emissions that can obscure the signals we want to measure. “
In the journal Optical Society (OSA) Applied optics, the researchers show that the metamaterial microwave slabs they developed absorb more than 99 percent of millimeter wave radiation and retain their properties at very low temperatures in the the millimeter wave camera is working.
“Because the tiles can be made by injecting commercially available materials, they are an economical, mass-produced and easy-to-apply solution to what has long been a problem, “Xu said. “With this technology, the Simons Observatory will change our understanding of the universe from many angles, including the beginning of the universe, the creation and evolution of the galaxies and the diminution of the first stars.”
Working at low temperatures
Ground-based millimeter wave telescopes use cryogenic temperature-cooled capture devices to reduce noise and thus increase sensitivity. Disposal technology has advanced to the point where any amount of stray light can reduce the image while also reducing the sensitivity of the detector. A better way to remove stray light inside the receivers would be to make more sense of the faint signals coming from depths within a space.
However, developing a material that can distract light while operating at such low temperatures is very challenging. Previous attempts resulted in materials that could not be cooled efficiently to cryogenic temperatures or did not achieve the required combination of low viscosity and high absorption. Other solutions have also been difficult to install or challenging to mass production.
To overcome these challenges, the researchers turned to metamaterials because they can be engineered to achieve specific properties that do not occur in nature. After complex electromagnetic simulation studies, the researchers designed metamaterials based on a material that combined carbon and plastic grains.
Reducing reflection
Although the plastic material showed full inclusion in the desired microwave section of the electromagnetic spectrum, the surface was exposed to a lot of radiation before it could penetrate the material for inclusion. . To reduce the shadow, the researchers applied a reflective face mask that was specifically designed using a spray nozzle.
“The low-shadow surface combined with high-absorbency material allows the metamaterial absorber slabs to deliver an excellent range of unwanted signals at cryogenic temperatures close to zero,” Xu said.
After ensuring that slabs made of the new metamaterial could survive mechanically from room temperature to cryogenic temperature, the researchers proved that they could be cooled efficiently to 27272 °. C (-458 ° F) and then measure the optical performance. “We developed a custom test facility to measure tile performance with full confidence,” said Grace Chesmore, a graduate student at the University of Chicago who led the optical measurement of this research. The experiment showed that the metamaterial properties exhibited excellent reflection properties with low scattering and captured almost all of the incoming photons.
“As detector sensitivity continues to improve for millimeter wave telescopes, it is critical to control scattered photons,” Xu said. “The successful combination of metamaterial fabrication and injection molding opens up many opportunities for scientific instrument design of millimeter wave instrument.”
###
The work was the result of a major global collaboration that included researchers from the University of Pennsylvania, the University of Chicago, the Goddard Space Flight Center, the Massachusetts Institute of Technology and other institutions.
Paper: Z. Xu, GE Chesmore, S. Adachi, AM Ali, A. Bazarko, G. Coppi, M. Devlin, T. Devlin, SR Dicker, PA Gallardo, JE Golec, JE Gudmundsson, K. Harrington, M. Hattori, A. Kofman, K. Kiuchi, A. Kusaka, M. Limon, F. Matsuda, J. McMahon, F. Nati, MD Niemack, A. Suzuki, GP Teply, RJ Thornton, EJ Wollack, M. Zannoni, N. Zhu, “Simons Theater: Absorber Metamaterial Microwave (MMA) and its Cryogenic Applications,” Applied optics, 60, 4, 864-874 (2021). DOI: https: /
Disclaimer: AAAS and EurekAlert! they are not responsible for the accuracy of press releases posted to EurekAlert! by sending institutions or for using any information through the EurekAlert system.