New ‘Nano Drum’ Lets Astronomers Listen Into The Cosmic Beat Of The Big Bang

New ‘Nano Drum’ Lets Astronomers Listen Into The Cosmic Beat Of The Big Bang

The universe might be mostly empty space, but it can be quite noisy when you’re hunting for incredibly faint signals floating through the aether. Radio telescopes have helped us map distant objects, search for extraterrestrial life, and learn about the birth of the universe, but a new vibrating membrane radio detector created by a group of Danish researchers could help silence some of that background noise and make it easier to see what’s really going on out there.

The new device is essentially a membrane capable of picking up extremely weak radio signals and converting them directly to light. Not only is that functionality highly desirable, the design is considerably more versatile than existing high-power radio detectors. When dealing with faint signals, even tiny amounts of heat in electronic equipment can drown out the signal with noise. To combat this, most existing detectors are cooled with liquid helium to just 4 Kelvin (-269C, -452F). This new drum-shaped detector membrane, amazingly, can operate at room temperature with almost no signal noise.

The device is based on a simple LC circuit — an inductor acts as a resonator for the radio and microwave signals (L) then transfers that signal to a capacitor (C). The design of the capacitor is what makes this detector new and potentially revolutionary. One of the metal plates in the capacitor is replaced with a 50 nanometer thick membrane of silicon nitrate coated with aluminum. So how does it outperform current radio signal detectors? That silicon nitrite membrane acts as a tiny woofer to amplify signals.

The team bounced a laser off the aluminum surface to detect the miniscule vibrations and measure the shifts in the reflected light. The upshot is that any signal — be it from a distant alien civilization or the big bang — above the background noise produced by this detector can be transmitted along a fiber optic cable in one step with virtually no loss of fidelity or interference [Research paper: doi:10.1038/nature13029 - "Optical detection of radio waves through a nanomechanical transducer"].

Even this first iteration of the membrane detector can perform as well at room temperature as current helium-cooled devices and that could be huge for radio astronomy going forward. As we peer deeper into space, we’re also looking back in time. Exploring the cosmic background radiation — the echo of the Big Bang — gives us hints about the origins and structure of the universe. This tiny drum-shaped detector might let us look deeper than ever before.

Other teams are looking at this design in hopes of adapting it for other applications like miniaturizing MRI machines, which currently have to cool the signal amplifiers with liquid helium. The University of Copenhagen team believes the room-temperature nature of its laser membrane detector could make the technology practical in a few short years.