How a single atomic sensor can help track Earth’s glaciers

Earth observations are one of the important features of our present fleet of satellites. Sometimes, every satellite focuses on one form of distant sensing—monitoring ocean ranges, for instance, or watching clouds develop and transfer. That’s primarily as a result of constraints of their sensors—notably the radar.

Nonetheless, a new kind of sensor present process improvement may change the sport in distant Earth sensing.

That new sensor expertise is called a Rydberg sensor, and it makes use of quantum theory to detect a broad band of radar indicators unexpectedly. Darmindra Arumugam of NASA’s Jet Propulsion Laboratory, who focuses on distant sensing and has labored with the expertise for years, shall be engaged on the event.

So why are Rydberg sensors so particular?

In a typical remote sensing software, a sensor is launched on a satellite that is excellent at detecting a selected frequency of sunshine. In radar phrases, these are damaged up into a number of totally different “bands,” every protecting wherever from a couple of megahertz to a couple gigahertz. Some are extra acquainted than others, resembling UHF (ultra-high frequency—300–1,000 MHz), however some are extra esoteric, such because the Ku band from 12–18 GHz.

Every of those bands is nice at monitoring one explicit system again on Earth. For instance, NASA makes use of the VHF (30–300 MHz) to review Earth’s tomography and the UHF band to review snow and rainfall.

Nonetheless, every of those frequencies would require its personal specifically designed antenna to detect, so any system that may try and have detection capabilities over a variety of frequencies, and thereby be monitoring a variety of various methods, would get increasingly costly as further bands have been added to the system.

That is the place Rydberg sensors are available in. They’re a novel sort of sensor that makes use of the quantum state of a single atom to detect a broad band of various electromagnetic waves. For instance, a single Rydberg sensor may detect indicators from the HF band all the way in which up by way of the Ka-band on the sooner finish of the radar spectrum. This may permit a satellite with a single sensor to observe all of the totally different methods that radar can detect remotely.

Explaining the functioning of a Rydberg sensor requires a comparatively full understanding of quantum mechanics. Rydberg sensors are named after a quantum state often known as the Rydberg state, which is awfully delicate to its atmosphere.

To get to the Rydberg state, engineers should zap a single atom of Rubidium or Cesium with a laser to make it develop to a very giant state—nearly to the scale of a micro organism. They then optically monitor adjustments within the atom, which is affected by indicators within the radar bands beforehand talked about.

The supporting optical system then analyzes the adjustments within the atom and might correlate these adjustments to adjustments within the sign at a selected frequency band.

A number of proofs of ideas have already been proven, resembling these offered by the Nationwide Institutes of Requirements and Know-how. However they’ve but to be utilized to space—and that’s the place Dr. Arumugam’s analysis is available in. His mission is to develop a Rydberg sensor that may be launched on a satellite and detect a broad band of radar indicators, together with people who monitor the cryosphere, the place ice and snow are current on land.

With a single Rydberg sensor, Dr. Arumugam hopes to seize all the info for an entire image of how Earth’s glaciers, snow soften, and ice pack change over time.

That’s nonetheless a great distance off, as rides into space aren’t well-known for being mild, and thus far, Rydberg sensors have solely ever been proven to work in a lab. However, provided that the expertise is barely ten years previous, there’s a lot potential room for enchancment.

As Dr. Arumugam says on the finish of his proposal write-up, this expertise “[has great] potential to generate curiosity inside NASA, the general public, and trade… ” If it really works how theorists anticipate it to, he shall be confirmed proper.